Articles | Volume 15, issue 1
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Impacts of the seasonal distribution of rainfall on vegetation productivity across the Sahel
International Institute for Earth System Sciences, Nanjing University, 210023 Nanjing, China
Department of Geosciences and Natural Resource Management, University of Copenhagen, 1350 Copenhagen, Denmark
Department of Geosciences and Natural Resource Management, University of Copenhagen, 1350 Copenhagen, Denmark
Department of Geosciences and Natural Resource Management, University of Copenhagen, 1350 Copenhagen, Denmark
International Institute for Earth System Sciences, Nanjing University, 210023 Nanjing, China
No articles found.
Xingyi Huang, Yuwei Yin, Luwei Feng, Xiaoye Tong, Xiaoxin Zhang, Jiangrong Li, and Feng Tian
Earth Syst. Sci. Data Discuss.,
Preprint under review for ESSDShort summary
The Tibetan Plateau, with its diverse vegetation from forests to alpine grasslands, plays a key role in understanding climate change impacts. Existing maps lack detail or miss unique ecosystems. Our research, using advanced satellite technology and machine learning, produced the TP_LC10-2022 map. Comparisons with other maps revealed TP_LC10-2022's excellence in capturing local variations. Our map is significant for in-depth ecological studies.
Søren J. Kragh, Rasmus Fensholt, Simon Stisen, and Julian Koch
Hydrol. Earth Syst. Sci., 27, 2463–2478,Short summary
This study investigates the precision of irrigation estimates from a global hotspot of unsustainable irrigation practice, the Indus and Ganges basins. We show that irrigation water use can be estimated with high precision by comparing satellite and rainfed hydrological model estimates of evapotranspiration. We believe that our work can support sustainable water resource management, as it addresses the uncertainty of a key component of the water balance that remains challenging to quantify.
Søren Julsgaard Kragh, Jacopo Dari, Sara Modanesi, Christian Massari, Luca Brocca, Rasmus Fensholt, Simon Stisen, and Julian Koch
Hydrol. Earth Syst. Sci. Discuss.,
Preprint under review for HESSShort summary
This study provides a comparison of methodologies to quantify irrigation to enhance regional irrigation estimates. To evaluate the methodologies, we compared various approaches to quantify irrigation using either soil moisture, evapotranspiration, or both within a novel baseline framework, together with irrigation estimates from other studies. We show, that the synergy from using two equally important components in joint approach within a baseline framework, yield better irrigation estimates.
Rena Meyer, Wenmin Zhang, Søren Julsgaard Kragh, Mie Andreasen, Karsten Høgh Jensen, Rasmus Fensholt, Simon Stisen, and Majken C. Looms
Hydrol. Earth Syst. Sci., 26, 3337–3357,Short summary
The amount and spatio-temporal distribution of soil moisture, the water in the upper soil, is of great relevance for agriculture and water management. Here, we investigate whether the established downscaling algorithm combining different satellite products to estimate medium-scale soil moisture is applicable to higher resolutions and whether results can be improved by accounting for land cover types. Original satellite data and downscaled soil moisture are compared with ground observations.
M. C. A. Picoli, J. Radoux, X. Tong, A. Bey, P. Rufin, M. Brandt, R. Fensholt, and P. Meyfroidt
Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLIII-B3-2022, 975–981,
Wim Verbruggen, Guy Schurgers, Stéphanie Horion, Jonas Ardö, Paulo N. Bernardino, Bernard Cappelaere, Jérôme Demarty, Rasmus Fensholt, Laurent Kergoat, Thomas Sibret, Torbern Tagesson, and Hans Verbeeck
Biogeosciences, 18, 77–93,Short summary
A large part of Earth's land surface is covered by dryland ecosystems, which are subject to climate extremes that are projected to increase under future climate scenarios. By using a mathematical vegetation model, we studied the impact of single years of extreme rainfall on the vegetation in the Sahel. We found a contrasting response of grasses and trees to these extremes, strongly dependent on the way precipitation is spread over the rainy season, as well as a long-term impact on CO2 uptake.
Nemesio J. Rodríguez-Fernández, Arnaud Mialon, Stephane Mermoz, Alexandre Bouvet, Philippe Richaume, Ahmad Al Bitar, Amen Al-Yaari, Martin Brandt, Thomas Kaminski, Thuy Le Toan, Yann H. Kerr, and Jean-Pierre Wigneron
Biogeosciences, 15, 4627–4645,Short summary
Existing global scale above-ground biomass (AGB) maps are made at very high spatial resolution collecting data during several years. In this paper we discuss the use of a new data set from the SMOS satellite: the vegetation optical depth estimated from low microwave frequencies. It is shown that this new data set is highly sensitive to AGB. The spacial resolution of SMOS is coarse (40 km) but the new data set can be used to monitor AGB variations with time due to its high revisit frequency.
S. Salehi, M. Karami, and R. Fensholt
Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLI-B7, 973–979,
Gregor Ratzmann, Ute Gangkofner, Britta Tietjen, and Rasmus Fensholt
Revised manuscript not acceptedShort summary
Anticipating impacts of changes in rainfall regimes on dryland ecosystems requires the understanding of the functional response to rainfall of those water limited environments. Here we show for two arid/semi-arid African regions based on satellite data that higher rainfall variability leads to a more dynamic vegetation response to rainfall. This applies irrespective of vegetation type. It moreover indicates that regions experiencing a higher rainfall variability may be more resilient to drought.
T. Tagesson, R. Fensholt, S. Huber, S. Horion, I. Guiro, A. Ehammer, and J. Ardö
Biogeosciences, 12, 4621–4635,Short summary
Relationships between ecosystem properties of semi-arid savanna and reflected solar radiance between 35 and 1800nm were investigated. Normalised combinations of reflectance for the near infrared, shortwave infrared, and 600 to 700nm were strongly affected by solar and viewing angle effects. Ecosystem properties of savannas were strongly correlated with reflectance at 350-1800nm, and normalised combinations of reflectance were strong predictors of the savanna ecosystem properties.
J. L. Olsen, S. Miehe, P. Ceccato, and R. Fensholt
Biogeosciences, 12, 4407–4419,Short summary
Limitations of satellite-based normalized difference vegetation index (NDVI) for monitoring vegetation trends are investigated using observations from the Widou Thiengoly test site in northern Senegal. NDVI do not reflect the large differences found in biomass production and species composition between grazed and ungrazed plots. This is problematic for vegetation trend analysis in the context of drastically increasing numbers of Sahelian livestock in recent decades.
R. Guzinski, H. Nieto, S. Stisen, and R. Fensholt
Hydrol. Earth Syst. Sci., 19, 2017–2036,Short summary
The study compared evapotranspiration (ET) modelled by two remote sensing models and one hydrological model in a river catchment in Denmark. The results show that the spatial patterns of ET produced by the remote sensing models are more similar to each other than to the fluxes produced by the hydrological model. This indicates potential benefits to the hydrological modelling community from integrating spatial information derived through remote sensing methodology into the hydrological models.
Related subject area
Earth System Science/Response to Global Change: Climate ChangeSimulated responses of soil carbon to climate change in CMIP6 Earth system models: the role of false primingAlkalinity biases in CMIP6 Earth system models and implications for simulated CO2 drawdown via artificial alkalinity enhancementExperiments of the efficacy of tree ring blue intensity as a climate proxy in central and western ChinaBurned area and carbon emissions across northwestern boreal North America from 2001–2019Quantifying land carbon cycle feedbacks under negative CO2 emissionsThe potential of an increased deciduous forest fraction to mitigate the effects of heat extremes in EuropeIdeas and perspectives: Alleviation of functional limitations by soil organisms is key to climate feedbacks from arctic soilsA comparison of the climate and carbon cycle effects of carbon removal by afforestation and an equivalent reduction in fossil fuel emissionsThe response of wildfire regimes to Last Glacial Maximum carbon dioxide and climateStability of alkalinity in ocean alkalinity enhancement (OAE) approaches – consequences for durability of CO2 storageIdeas and perspectives: Land–ocean connectivity through groundwaterBioclimatic change as a function of global warming from CMIP6 climate projectionsReconciling different approaches to quantifying land surface temperature impacts of afforestation using satellite observationsDrivers of intermodel uncertainty in land carbon sink projectionsReviews and syntheses: A framework to observe, understand and project ecosystem response to environmental change in the East Antarctic Southern OceanAcidification impacts and acclimation potential of Caribbean benthic foraminifera assemblages in naturally discharging low-pH waterMonitoring vegetation condition using microwave remote sensing: the standardized vegetation optical depth index (SVODI)Evaluation of soil carbon simulation in CMIP6 Earth system modelsDiazotrophy as a key driver of the response of marine net primary productivity to climate changeImpact of negative and positive CO2 emissions on global warming metrics using an ensemble of Earth system model simulationsAcidification, deoxygenation, and nutrient and biomass declines in a warming Mediterranean SeaOcean alkalinity enhancement – avoiding runaway CaCO3 precipitation during quick and hydrated lime dissolutionAssessment of the impacts of biological nitrogen fixation structural uncertainty in CMIP6 earth system modelsAnthropogenic climate change drives non-stationary phytoplankton varianceSoil carbon loss in warmed subarctic grasslands is rapid and restricted to topsoilThe European forest carbon budget under future climate conditions and current management practicesThe influence of mesoscale climate drivers on hypoxia in a fjord-like deep coastal inlet and its potential implications regarding climate change: examining a decade of water quality dataContrasting responses of phytoplankton productivity between coastal and offshore surface waters in the Taiwan Strait and the South China Sea to short-term seawater acidificationModeling interactions between tides, storm surges, and river discharges in the Kapuas River deltaThe application of dendrometers to alpine dwarf shrubs – a case study to investigate stem growth responses to environmental conditionsClimate, land cover and topography: essential ingredients in predicting wetland permanenceNot all biodiversity rich spots are climate refugiaEvaluating the dendroclimatological potential of blue intensity on multiple conifer species from Tasmania and New ZealandAnthropogenic CO2-mediated freshwater acidification limits survival, calcification, metabolism, and behaviour in stress-tolerant freshwater crustaceansQuantifying the role of moss in terrestrial ecosystem carbon dynamics in northern high latitudesOn the influence of erect shrubs on the irradiance profile in snowTolerance of tropical marine microphytobenthos exposed to elevated irradiance and temperaturePersistent impacts 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Rebecca M. Varney, Sarah E. Chadburn, Eleanor J. Burke, Simon Jones, Andy J. Wiltshire, and Peter M. Cox
Biogeosciences, 20, 3767–3790,Short summary
This study evaluates soil carbon projections during the 21st century in CMIP6 Earth system models. In general, we find a reduced spread of changes in global soil carbon in CMIP6 compared to the previous CMIP5 generation. The reduced CMIP6 spread arises from an emergent relationship between soil carbon changes due to change in plant productivity and soil carbon changes due to changes in turnover time. We show that this relationship is consistent with false priming under transient climate change.
Claudia Hinrichs, Peter Köhler, Christoph Völker, and Judith Hauck
Biogeosciences, 20, 3717–3735,Short summary
This study evaluated the alkalinity distribution in 14 climate models and found that most models underestimate alkalinity at the surface and overestimate it in the deeper ocean. It highlights the need for better understanding and quantification of processes driving alkalinity distribution and calcium carbonate dissolution and the importance of accounting for biases in model results when evaluating potential ocean alkalinity enhancement experiments.
Yonghong Zheng, Huanfeng Shen, Rory Abernethy, and Rob Wilson
Biogeosciences, 20, 3481–3490,Short summary
Investigations in central and western China show that tree ring inverted latewood intensity expresses a strong positive relationship with growing-season temperatures, indicating exciting potential for regions south of 30° N that are traditionally not targeted for temperature reconstructions. Earlywood BI also shows good potential to reconstruct hydroclimate parameters in some humid areas and will enhance ring-width-based hydroclimate reconstructions in the future.
Stefano Potter, Sol Cooperdock, Sander Veraverbeke, Xanthe Walker, Michelle C. Mack, Scott J. Goetz, Jennifer Baltzer, Laura Bourgeau-Chavez, Arden Burrell, Catherine Dieleman, Nancy French, Stijn Hantson, Elizabeth E. Hoy, Liza Jenkins, Jill F. Johnstone, Evan S. Kane, Susan M. Natali, James T. Randerson, Merritt R. Turetsky, Ellen Whitman, Elizabeth Wiggins, and Brendan M. Rogers
Biogeosciences, 20, 2785–2804,Short summary
Here we developed a new burned-area detection algorithm between 2001–2019 across Alaska and Canada at 500 m resolution. We estimate 2.37 Mha burned annually between 2001–2019 over the domain, emitting 79.3 Tg C per year, with a mean combustion rate of 3.13 kg C m−2. We found larger-fire years were generally associated with greater mean combustion. The burned-area and combustion datasets described here can be used for local- to continental-scale applications of boreal fire science.
V. Rachel Chimuka, Claude-Michel Nzotungicimpaye, and Kirsten Zickfeld
Biogeosciences, 20, 2283–2299,Short summary
We propose a new method to quantify carbon cycle feedbacks under negative CO2 emissions. Our method isolates the lagged carbon cycle response to preceding positive emissions from the response to negative emissions. Our findings suggest that feedback parameters calculated with the novel approach are larger than those calculated with the conventional approach whereby carbon cycle inertia is not corrected for, with implications for the effectiveness of carbon dioxide removal in reducing CO2 levels.
Marcus Breil, Annabell Weber, and Joaquim G. Pinto
Biogeosciences, 20, 2237–2250,Short summary
A promising strategy for mitigating burdens of heat extremes in Europe is to replace dark coniferous forests with brighter deciduous forests. The consequence of this would be reduced absorption of solar radiation, which should reduce the intensities of heat periods. In this study, we show that deciduous forests have a certain cooling effect on heat period intensities in Europe. However, the magnitude of the temperature reduction is quite small.
Gesche Blume-Werry, Jonatan Klaminder, Eveline J. Krab, and Sylvain Monteux
Biogeosciences, 20, 1979–1990,Short summary
Northern soils store a lot of carbon. Most research has focused on how this carbon storage is regulated by cold temperatures. However, it is soil organisms, from minute bacteria to large earthworms, that decompose the organic material. Novel soil organisms from further south could increase decomposition rates more than climate change does and lead to carbon losses. We therefore advocate for including soil organisms when predicting the fate of soil functions in warming northern ecosystems.
Koramanghat Unnikrishnan Jayakrishnan and Govindasamy Bala
Biogeosciences, 20, 1863–1877,Short summary
Afforestation and reducing fossil fuel emissions are two important mitigation strategies to reduce the amount of global warming. Our work shows that reducing fossil fuel emissions is relatively more effective than afforestation for the same amount of carbon removed from the atmosphere. However, understanding of the processes that govern the biophysical effects of afforestation should be improved before considering our results for climate policy.
Olivia Haas, Iain Colin Prentice, and Sandy P. Harrison
We quantify the impact of CO2 and climate on global patterns of burnt area, fire size and intensity under Last Glacial Maximum (LGM) conditions, using three climate scenarios. Climate change alone did not produce the observed LGM reduction in burnt area, but low CO2 did through reducing vegetation productivity. Fire intensity was sensitive to CO2 but strongly affected by changes in atmospheric dryness. Low CO2 caused smaller fires; climate had the opposite effect except in the driest scenario.
Jens Hartmann, Niels Suitner, Carl Lim, Julieta Schneider, Laura Marín-Samper, Javier Arístegui, Phil Renforth, Jan Taucher, and Ulf Riebesell
Biogeosciences, 20, 781–802,Short summary
CO2 can be stored in the ocean via increasing alkalinity of ocean water. Alkalinity can be created via dissolution of alkaline materials, like limestone or soda. Presented research studies boundaries for increasing alkalinity in seawater. The best way to increase alkalinity was found using an equilibrated solution, for example as produced from reactors. Adding particles for dissolution into seawater on the other hand produces the risk of losing alkalinity and degassing of CO2 to the atmosphere.
Damian L. Arévalo-Martínez, Amir Haroon, Hermann W. Bange, Ercan Erkul, Marion Jegen, Nils Moosdorf, Jens Schneider von Deimling, Christian Berndt, Michael Ernst Böttcher, Jasper Hoffmann, Volker Liebetrau, Ulf Mallast, Gudrun Massmann, Aaron Micallef, Holly A. Michael, Hendrik Paasche, Wolfgang Rabbel, Isaac Santos, Jan Scholten, Katrin Schwalenberg, Beata Szymczycha, Ariel T. Thomas, Joonas J. Virtasalo, Hannelore Waska, and Bradley A. Weymer
Biogeosciences, 20, 647–662,Short summary
Groundwater flows at the land–ocean transition and the extent of freshened groundwater below the seafloor are increasingly relevant in marine sciences, both because they are a highly uncertain term of biogeochemical budgets and due to the emerging interest in the latter as a resource. Here, we discuss our perspectives on future research directions to better understand land–ocean connectivity through groundwater and its potential responses to natural and human-induced environmental changes.
Morgan Sparey, Peter Cox, and Mark S. Williamson
Biogeosciences, 20, 451–488,Short summary
Accurate climate models are vital for mitigating climate change; however, projections often disagree. Using Köppen–Geiger bioclimate classifications we show that CMIP6 climate models agree well on the fraction of global land surface that will change classification per degree of global warming. We find that 13 % of land will change climate per degree of warming from 1 to 3 K; thus, stabilising warming at 1.5 rather than 2 K would save over 7.5 million square kilometres from bioclimatic change.
Huanhuan Wang, Chao Yue, and Sebastiaan Luyssaert
Biogeosciences, 20, 75–92,Short summary
This study provided a synthesis of three influential methods to quantify afforestation impact on surface temperature. Results showed that actual effect following afforestation was highly dependent on afforestation fraction. When full afforestation is assumed, the actual effect approaches the potential effect. We provided evidence the afforestation faction is a key factor in reconciling different methods and emphasized that it should be considered for surface cooling impacts in policy evaluation.
Ryan S. Padrón, Lukas Gudmundsson, Laibao Liu, Vincent Humphrey, and Sonia I. Seneviratne
Biogeosciences, 19, 5435–5448,Short summary
The answer to how much carbon land ecosystems are projected to remove from the atmosphere until 2100 is different for each Earth system model. We find that differences across models are primarily explained by the annual land carbon sink dependence on temperature and soil moisture, followed by the dependence on CO2 air concentration, and by average climate conditions. Our insights on why each model projects a relatively high or low land carbon sink can help to reduce the underlying uncertainty.
Julian Gutt, Stefanie Arndt, David Keith Alan Barnes, Horst Bornemann, Thomas Brey, Olaf Eisen, Hauke Flores, Huw Griffiths, Christian Haas, Stefan Hain, Tore Hattermann, Christoph Held, Mario Hoppema, Enrique Isla, Markus Janout, Céline Le Bohec, Heike Link, Felix Christopher Mark, Sebastien Moreau, Scarlett Trimborn, Ilse van Opzeeland, Hans-Otto Pörtner, Fokje Schaafsma, Katharina Teschke, Sandra Tippenhauer, Anton Van de Putte, Mia Wege, Daniel Zitterbart, and Dieter Piepenburg
Biogeosciences, 19, 5313–5342,Short summary
Long-term ecological observations are key to assess, understand and predict impacts of environmental change on biotas. We present a multidisciplinary framework for such largely lacking investigations in the East Antarctic Southern Ocean, combined with case studies, experimental and modelling work. As climate change is still minor here but is projected to start soon, the timely implementation of this framework provides the unique opportunity to document its ecological impacts from the very onset.
Daniel François, Adina Paytan, Olga Maria Oliveira de Araújo, Ricardo Tadeu Lopes, and Cátia Fernandes Barbosa
Biogeosciences, 19, 5269–5285,Short summary
Our analysis revealed that under the two most conservative acidification projections foraminifera assemblages did not display considerable changes. However, a significant decrease in species richness was observed when pH decreases to 7.7 pH units, indicating adverse effects under high-acidification scenarios. A micro-CT analysis revealed that calcified tests of Archaias angulatus were of lower density in low pH, suggesting no acclimation capacity for this species.
Leander Moesinger, Ruxandra-Maria Zotta, Robin van der Schalie, Tracy Scanlon, Richard de Jeu, and Wouter Dorigo
Biogeosciences, 19, 5107–5123,Short summary
The standardized vegetation optical depth index (SVODI) can be used to monitor the vegetation condition, such as whether the vegetation is unusually dry or wet. SVODI has global coverage, spans the past 3 decades and is derived from multiple spaceborne passive microwave sensors of that period. SVODI is based on a new probabilistic merging method that allows the merging of normally distributed data even if the data are not gap-free.
Rebecca M. Varney, Sarah E. Chadburn, Eleanor J. Burke, and Peter M. Cox
Biogeosciences, 19, 4671–4704,Short summary
Soil carbon is the Earth’s largest terrestrial carbon store, and the response to climate change represents one of the key uncertainties in obtaining accurate global carbon budgets required to successfully militate against climate change. The ability of climate models to simulate present-day soil carbon is therefore vital. This study assesses soil carbon simulation in the latest ensemble of models which allows key areas for future model development to be identified.
Laurent Bopp, Olivier Aumont, Lester Kwiatkowski, Corentin Clerc, Léonard Dupont, Christian Ethé, Thomas Gorgues, Roland Séférian, and Alessandro Tagliabue
Biogeosciences, 19, 4267–4285,Short summary
The impact of anthropogenic climate change on the biological production of phytoplankton in the ocean is a cause for concern because its evolution could affect the response of marine ecosystems to climate change. Here, we identify biological N fixation and its response to future climate change as a key process in shaping the future evolution of marine phytoplankton production. Our results show that further study of how this nitrogen fixation responds to environmental change is essential.
Negar Vakilifard, Richard G. Williams, Philip B. Holden, Katherine Turner, Neil R. Edwards, and David J. Beerling
Biogeosciences, 19, 4249–4265,Short summary
To remain within the Paris climate agreement, there is an increasing need to develop and implement carbon capture and sequestration techniques. The global climate benefits of implementing negative emission technologies over the next century are assessed using an Earth system model covering a wide range of plausible climate states. In some model realisations, there is continued warming after emissions cease. This continued warming is avoided if negative emissions are incorporated.
Marco Reale, Gianpiero Cossarini, Paolo Lazzari, Tomas Lovato, Giorgio Bolzon, Simona Masina, Cosimo Solidoro, and Stefano Salon
Biogeosciences, 19, 4035–4065,Short summary
Future projections under the RCP8.5 and RCP4.5 emission scenarios of the Mediterranean Sea biogeochemistry at the end of the 21st century show different levels of decline in nutrients, oxygen and biomasses and an acidification of the water column. The signal intensity is stronger under RCP8.5 and in the eastern Mediterranean. Under RCP4.5, after the second half of the 21st century, biogeochemical variables show a recovery of the values observed at the beginning of the investigated period.
Charly A. Moras, Lennart T. Bach, Tyler Cyronak, Renaud Joannes-Boyau, and Kai G. Schulz
Biogeosciences, 19, 3537–3557,Short summary
This research presents the first laboratory results of quick and hydrated lime dissolution in natural seawater. These two minerals are of great interest for ocean alkalinity enhancement, a strategy aiming to decrease atmospheric CO2 concentrations. Following the dissolution of these minerals, we identified several hurdles and presented ways to avoid them or completely negate them. Finally, we proceeded to various simulations in today’s oceans to implement the strategy at its highest potential.
Taraka Davies-Barnard, Sönke Zaehle, and Pierre Friedlingstein
Biogeosciences, 19, 3491–3503,Short summary
Biological nitrogen fixation is the largest natural input of new nitrogen onto land. Earth system models mainly represent global total terrestrial biological nitrogen fixation within observational uncertainties but overestimate tropical fixation. The model range of increase in biological nitrogen fixation in the SSP3-7.0 scenario is 3 % to 87 %. While biological nitrogen fixation is a key source of new nitrogen, its predictive power for net primary productivity in models is limited.
Geneviève W. Elsworth, Nicole S. Lovenduski, Kristen M. Krumhardt, Thomas M. Marchitto, and Sarah Schlunegger
Anthropogenic climate change will influence marine phytoplankton over the coming century. Here, we quantify the influence of anthropogenic climate change on marine phytoplankton variance using an Earth System Model ensemble, identifying a decline in global phytoplankton biomass variance with warming. Our results suggest that climate mitigation efforts that account for marine phytoplankton changes should also consider changes in phytoplankton variance driven by anthropogenic warming.
Niel Verbrigghe, Niki I. W. Leblans, Bjarni D. Sigurdsson, Sara Vicca, Chao Fang, Lucia Fuchslueger, Jennifer L. Soong, James T. Weedon, Christopher Poeplau, Cristina Ariza-Carricondo, Michael Bahn, Bertrand Guenet, Per Gundersen, Gunnhildur E. Gunnarsdóttir, Thomas Kätterer, Zhanfeng Liu, Marja Maljanen, Sara Marañón-Jiménez, Kathiravan Meeran, Edda S. Oddsdóttir, Ivika Ostonen, Josep Peñuelas, Andreas Richter, Jordi Sardans, Páll Sigurðsson, Margaret S. Torn, Peter M. Van Bodegom, Erik Verbruggen, Tom W. N. Walker, Håkan Wallander, and Ivan A. Janssens
Biogeosciences, 19, 3381–3393,Short summary
In subarctic grassland on a geothermal warming gradient, we found large reductions in topsoil carbon stocks, with carbon stocks linearly declining with warming intensity. Most importantly, however, we observed that soil carbon stocks stabilised within 5 years of warming and remained unaffected by warming thereafter, even after > 50 years of warming. Moreover, in contrast to the large topsoil carbon losses, subsoil carbon stocks remained unaffected after > 50 years of soil warming.
Roberto Pilli, Ramdane Alkama, Alessandro Cescatti, Werner A. Kurz, and Giacomo Grassi
Biogeosciences, 19, 3263–3284,Short summary
To become carbon neutral by 2050, the European Union (EU27) forest C sink should increase to −450 Mt CO2 yr-1. Our study highlights that under current management practices (i.e. excluding any policy scenario) the forest C sink of the EU27 member states and the UK may decrease to about −250 Mt CO2eq yr-1 in 2050. The expected impacts of future climate change, however, add a considerable uncertainty, potentially nearly doubling or halving the sink associated with forest management.
Johnathan Daniel Maxey, Neil David Hartstein, Aazani Mujahid, and Moritz Müller
Biogeosciences, 19, 3131–3150,Short summary
Deep coastal inlets are important sites for regulating land-based organic pollution before it enters coastal oceans. This study focused on how large climate forces, rainfall, and river flow impact organic loading and oxygen conditions in a coastal inlet in Tasmania. Increases in rainfall were linked to higher organic loading and lower oxygen in basin waters. Finally we observed a significant correlation between the Southern Annular Mode and oxygen concentrations in the system's basin waters.
Guang Gao, Tifeng Wang, Jiazhen Sun, Xin Zhao, Lifang Wang, Xianghui Guo, and Kunshan Gao
Biogeosciences, 19, 2795–2804,Short summary
After conducting large-scale deck-incubation experiments, we found that seawater acidification (SA) increased primary production (PP) in coastal waters but reduced it in pelagic zones, which is mainly regulated by local pH, light intensity, salinity, and community structure. In future oceans, SA combined with decreased upward transports of nutrients may synergistically reduce PP in pelagic zones.
Joko Sampurno, Valentin Vallaeys, Randy Ardianto, and Emmanuel Hanert
Biogeosciences, 19, 2741–2757,Short summary
This study is the first assessment to evaluate the interactions between river discharges, tides, and storm surges and how they can drive compound flooding in the Kapuas River delta. We successfully created a realistic hydrodynamic model whose domain covers the land–sea continuum using a wetting–drying algorithm in a data-scarce environment. We then proposed a new method to delineate compound flooding hazard zones along the river channels based on the maximum water level profiles.
Svenja Dobbert, Roland Pape, and Jörg Löffler
Biogeosciences, 19, 1933–1958,Short summary
Understanding how vegetation might respond to climate change is especially important in arctic–alpine ecosystems, where major shifts in shrub growth have been observed. We studied how such changes come to pass and how future changes might look by measuring hourly variations in the stem diameter of dwarf shrubs from one common species. From these data, we are able to discern information about growth mechanisms and can thus show the complexity of shrub growth and micro-environment relations.
Jody Daniel, Rebecca C. Rooney, and Derek T. Robinson
Biogeosciences, 19, 1547–1570,Short summary
The threat posed by climate change to prairie pothole wetlands is well documented, but gaps remain in our ability to make meaningful predictions about how prairie pothole wetlands will respond. We integrate aspects of topography, land cover/land use and climate to model the permanence class of tens of thousands of wetlands at the western edge of the Prairie Pothole Region.
Ádám T. Kocsis, Qianshuo Zhao, Mark J. Costello, and Wolfgang Kiessling
Biogeosciences, 18, 6567–6578,Short summary
Biodiversity is under threat from the effects of global warming, and assessing the effects of climate change on areas of high species richness is of prime importance to conservation. Terrestrial and freshwater rich spots have been and will be less affected by climate change than other areas. However, marine rich spots of biodiversity are expected to experience more pronounced warming.
Rob Wilson, Kathy Allen, Patrick Baker, Gretel Boswijk, Brendan Buckley, Edward Cook, Rosanne D'Arrigo, Dan Druckenbrod, Anthony Fowler, Margaux Grandjean, Paul Krusic, and Jonathan Palmer
Biogeosciences, 18, 6393–6421,Short summary
We explore blue intensity (BI) – a low-cost method for measuring ring density – to enhance palaeoclimatology in Australasia. Calibration experiments, using several conifer species from Tasmania and New Zealand, model 50–80 % of the summer temperature variance. The implications of these results have profound consequences for high-resolution paleoclimatology in Australasia, as the speed and cheapness of BI generation could lead to a step change in our understanding of past climate in the region.
Alex R. Quijada-Rodriguez, Pou-Long Kuan, Po-Hsuan Sung, Mao-Ting Hsu, Garett J. P. Allen, Pung Pung Hwang, Yung-Che Tseng, and Dirk Weihrauch
Biogeosciences, 18, 6287–6300,Short summary
Anthropogenic CO2 is chronically acidifying aquatic ecosystems. We aimed to determine the impact of future freshwater acidification on the physiology and behaviour of an important aquaculture crustacean, Chinese mitten crabs. We report that elevated freshwater CO2 levels lead to impairment of calcification, locomotor behaviour, and survival and reduced metabolism in this species. Results suggest that present-day calcifying invertebrates could be heavily affected by freshwater acidification.
Junrong Zha and Qianlai Zhuang
Biogeosciences, 18, 6245–6269,Short summary
This study incorporated moss into an extant biogeochemistry model to simulate the role of moss in carbon dynamics in the Arctic. The interactions between higher plants and mosses and their competition for energy, water, and nutrients are considered in our study. We found that, compared with the previous model without moss, the new model estimated a much higher carbon accumulation in the region during the last century and this century.
Maria Belke-Brea, Florent Domine, Ghislain Picard, Mathieu Barrere, and Laurent Arnaud
Biogeosciences, 18, 5851–5869,Short summary
Expanding shrubs in the Arctic change snowpacks into a mix of snow, impurities and buried branches. Snow is a translucent medium into which light penetrates and gets partly absorbed by branches or impurities. Measurements of light attenuation in snow in Northern Quebec, Canada, showed (1) black-carbon-dominated light attenuation in snowpacks without shrubs and (2) buried branches influence radiation attenuation in snow locally, leading to melting and pockets of large crystals close to branches.
Sazlina Salleh and Andrew McMinn
Biogeosciences, 18, 5313–5326,Short summary
The benthic diatom communities in Tanjung Rhu, Malaysia, were regularly exposed to high light and temperature variability during the tidal cycle, resulting in low photosynthetic efficiency. We examined the impact of high temperatures on diatoms' photosynthetic capacities, and temperatures beyond 50 °C caused severe photoinhibition. At the same time, those diatoms exposed to temperatures of 40 °C did not show any sign of photoinhibition.
Cornelius Senf and Rupert Seidl
Biogeosciences, 18, 5223–5230,Short summary
Europe was affected by an extreme drought in 2018. We show that this drought has increased forest disturbances across Europe, especially central and eastern Europe. Disturbance levels observed 2018–2020 were the highest on record for 30 years. Increased forest disturbances were correlated with low moisture and high atmospheric water demand. The unprecedented impacts of the 2018 drought on forest disturbances demonstrate an urgent need to adapt Europe’s forests to a hotter and drier future.
Jessica L. McCarty, Juha Aalto, Ville-Veikko Paunu, Steve R. Arnold, Sabine Eckhardt, Zbigniew Klimont, Justin J. Fain, Nikolaos Evangeliou, Ari Venäläinen, Nadezhda M. Tchebakova, Elena I. Parfenova, Kaarle Kupiainen, Amber J. Soja, Lin Huang, and Simon Wilson
Biogeosciences, 18, 5053–5083,Short summary
Fires, including extreme fire seasons, and fire emissions are more common in the Arctic. A review and synthesis of current scientific literature find climate change and human activity in the north are fuelling an emerging Arctic fire regime, causing more black carbon and methane emissions within the Arctic. Uncertainties persist in characterizing future fire landscapes, and thus emissions, as well as policy-relevant challenges in understanding, monitoring, and managing Arctic fire regimes.
Alexander J. Winkler, Ranga B. Myneni, Alexis Hannart, Stephen Sitch, Vanessa Haverd, Danica Lombardozzi, Vivek K. Arora, Julia Pongratz, Julia E. M. S. Nabel, Daniel S. Goll, Etsushi Kato, Hanqin Tian, Almut Arneth, Pierre Friedlingstein, Atul K. Jain, Sönke Zaehle, and Victor Brovkin
Biogeosciences, 18, 4985–5010,Short summary
Satellite observations since the early 1980s show that Earth's greening trend is slowing down and that browning clusters have been emerging, especially in the last 2 decades. A collection of model simulations in conjunction with causal theory points at climatic changes as a key driver of vegetation changes in natural ecosystems. Most models underestimate the observed vegetation browning, especially in tropical rainforests, which could be due to an excessive CO2 fertilization effect in models.
Vincent Niderkorn, Annette Morvan-Bertrand, Aline Le Morvan, Angela Augusti, Marie-Laure Decau, and Catherine Picon-Cochard
Biogeosciences, 18, 4841–4853,Short summary
Climate change can change vegetation characteristics in grasslands with a potential impact on forage chemical composition and quality, as well as its use by ruminants. Using controlled conditions mimicking a future climatic scenario, we show that forage quality and ruminant digestion are affected in opposite ways by elevated atmospheric CO2 and an extreme event (heat wave, severe drought), indicating that different factors of climate change have to be considered together.
Verónica Pancotto, David Holl, Julio Escobar, María Florencia Castagnani, and Lars Kutzbach
Biogeosciences, 18, 4817–4839,Short summary
We investigated the response of a wetland plant community to elevated temperature conditions in a cushion bog on Tierra del Fuego, Argentina. We measured carbon dioxide fluxes at experimentally warmed plots and at control plots. Warmed plant communities sequestered between 55 % and 85 % less carbon dioxide than untreated control cushions over the main growing season. Our results suggest that even moderate future warming could decrease the carbon sink function of austral cushion bogs.
Melissa A. Ward, Tessa M. Hill, Chelsey Souza, Tessa Filipczyk, Aurora M. Ricart, Sarah Merolla, Lena R. Capece, Brady C O'Donnell, Kristen Elsmore, Walter C. Oechel, and Kathryn M. Beheshti
Biogeosciences, 18, 4717–4732,Short summary
Salt marshes and seagrass meadows ("blue carbon" habitats) can sequester and store high levels of organic carbon (OC), helping to mitigate climate change. In California blue carbon sediments, we quantified OC storage and exchange between these habitats. We find that (1) these salt marshes store about twice as much OC as seagrass meadows do and (2), while OC from seagrass meadows is deposited into neighboring salt marshes, little of this material is sequestered as "long-term" carbon.
Damien Couespel, Marina Lévy, and Laurent Bopp
Biogeosciences, 18, 4321–4349,Short summary
An alarming consequence of climate change is the oceanic primary production decline projected by Earth system models. These coarse-resolution models parameterize oceanic eddies. Here, idealized simulations of global warming with increasing resolution show that the decline in primary production in the eddy-resolved simulations is half as large as in the eddy-parameterized simulations. This stems from the high sensitivity of the subsurface nutrient transport to model resolution.
Wu Ma, Lu Zhai, Alexandria Pivovaroff, Jacquelyn Shuman, Polly Buotte, Junyan Ding, Bradley Christoffersen, Ryan Knox, Max Moritz, Rosie A. Fisher, Charles D. Koven, Lara Kueppers, and Chonggang Xu
Biogeosciences, 18, 4005–4020,Short summary
We use a hydrodynamic demographic vegetation model to estimate live fuel moisture dynamics of chaparral shrubs, a dominant vegetation type in fire-prone southern California. Our results suggest that multivariate climate change could cause a significant net reduction in live fuel moisture and thus exacerbate future wildfire danger in chaparral shrub systems.
Bertold Mariën, Inge Dox, Hans J. De Boeck, Patrick Willems, Sebastien Leys, Dimitri Papadimitriou, and Matteo Campioli
Biogeosciences, 18, 3309–3330,Short summary
The drivers of the onset of autumn leaf senescence for several deciduous tree species are still unclear. Therefore, we addressed (i) if drought impacts the timing of autumn leaf senescence and (ii) if the relationship between drought and autumn leaf senescence depends on the tree species. Our study suggests that the timing of autumn leaf senescence is conservative across years and species and even independent of drought stress.
Anna Katavouta and Richard G. Williams
Biogeosciences, 18, 3189–3218,Short summary
Diagnostics of the latest-generation Earth system models reveal the ocean will continue to absorb a large fraction of the anthropogenic carbon released to the atmosphere in the next century, with the Atlantic Ocean storing a large amount of this carbon relative to its size. The ability of the ocean to absorb carbon will reduce in the future as the ocean warms and acidifies. This reduction is larger in the Atlantic Ocean due to a weakening of the meridional overturning with changes in climate.
Genevieve Jay Brett, Daniel B. Whitt, Matthew C. Long, Frank Bryan, Kate Feloy, and Kelvin J. Richards
Biogeosciences, 18, 3123–3145,Short summary
We quantify one form of uncertainty in modeled 21st-century changes in phytoplankton growth. The supply of nutrients from deep to surface waters decreases in the warmer future ocean, but the effect on phytoplankton growth also depends on changes in available light, how much light and nutrient the plankton need, and how fast they can grow. These phytoplankton properties can be summarized as a biological timescale: when it is short, future growth decreases twice as much as when it is long.
Sean M. Ridge and Galen A. McKinley
Biogeosciences, 18, 2711–2725,Short summary
Approximately 40 % of the CO2 emissions from fossil fuel combustion and cement production have been absorbed by the ocean. The goal of the UNFCCC Paris Agreement is to reduce humanity's emissions so as to limit global warming to no more than 2 °C, and ideally less than 1.5 °C. If we achieve this level of mitigation, the ocean's uptake of carbon will be strongly reduced. Excess carbon trapped in the near-surface ocean will begin to mix back to the surface and will limit additional uptake.
Alexander Koch, Chris Brierley, and Simon L. Lewis
Biogeosciences, 18, 2627–2647,Short summary
Estimates of large-scale tree planting and forest restoration as a carbon sequestration tool typically miss a crucial aspect: the Earth system response to the increased land carbon sink from new vegetation. We assess the impact of tropical forest restoration using an Earth system model under a scenario that limits warming to 2 °C. Almost two-thirds of the carbon impact of forest restoration is offset by negative carbon cycle feedbacks, suggesting a more modest benefit than in previous studies.
Abdi, A. M., Seaquist, J., Tenenbaum, D. E., Eklundh, L., and Ardö, J.: The supply and demand of net primary production in the Sahel, Environ. Res. Lett., 9, 94003, https://doi.org/10.1088/1748-9326/9/9/094003, 2014.
Archer, E.: Beyond the “climate versus grazing” impasse: using remote sensing to investigate the effects of grazing system choice on vegetation cover in the eastern, J. Arid Environ., 57, 381–408, https://doi.org/10.1016/S0140-1963(03)00107-1, 2004.
Bai, Z., Dent, D., and Olsson, L.: Proxy global assessment of land degradation, Soil Use Manage., 24, 223–234, https://doi.org/10.1111/j.1475-2743.2008.00169.x, 2008.
Bates, J. D., Svejcar, T., Miller, R. F., and Angell, R. A.: The effects of precipitation timing on sagebrush steppe vegetation, J. Arid Environ., 64, 670–697, https://doi.org/10.1016/j.jaridenv.2005.06.026, 2006.
Biasutti, M. and Sobel, A. H.: Delayed Sahel rainfall and global seasonal cycle in a warmer climate, Geophys. Res. Lett., 36, 1–5, https://doi.org/10.1029/2009GL041303, 2009.
Brandt, M., Tappan, G., Diouf, A., Beye, G., and Mbow, C.: Woody vegetation die off and regeneration in response to rainfall variability in the West African Sahel, Remote Sensing, 9, 39, https://doi.org/10.3390/rs9010039, 2017.
Breiman, L.: Random forests, Mach. Learn., 45, 5–32, https://doi.org/10.1023/A:1010933404324, 2001.
Breman, H. and Kessler, J.: Woody Plants in Agro-Ecosystems of Semi-Arid Regions: With an Emphasis on the Sahelian Countries, Springer, Berlin Heidelberg, 1995.
Chen, J., Chen, J., Liao, A., Cao, X., Chen, L., Chen, X., He, C., Han, G., Peng, S., Lu, M., Zhang, W., Tong, X., and Mills, J.: Global land cover mapping at 30 m resolution: a POK-based operational approach, ISPRS J. Photogramm., 103, 7–27, https://doi.org/10.1016/j.isprsjprs.2014.09.002, 2014.
Diaconescu, E. P., Gachon, P., Scinocca, J., and Laprise, R.: Evaluation of daily precipitation statistics and monsoon onset/retreat over western Sahel in multiple data sets, Clim. Dynam., 45(5–6), 1325–1354, https://doi.org/10.1007/s00382-014-2383-2, 2015.
Diouf, A. A., Hiernaux, P., Brandt, M., Faye, G., Djaby, B., Diop, M. B., Ndione, J. A., and Tychon, B.: Do agrometeorological data improve optical satellite-based estimations of the herbaceous yield in Sahelian semi-arid ecosystems?, Remote Sensing, 8, 668, https://doi.org/10.3390/rs8080668, 2016.
Donohue, R. J., Roderick, M. L., McVicar, T. R., and Farquhar, G. D.: Impact of CO2 fertilization on maximum foliage cover across the globe's warm, arid environments, Geophys. Res. Lett., 40, 3031–3035, https://doi.org/10.1002/grl.50563, 2013.
Dunning, C. M., Black, E. C. L., and Allan, R. P.: The onset and cessation of seasonal rainfall over Africa, J. Geophys. Res.-Atmos., 121, 11405–11424, https://doi.org/10.1002/2016JD025428, 2016.
Evans, J. and Geerken, R.: Discrimination between climate and human-induced dryland degradation, J. Arid Environ., 57, 535–554, https://doi.org/10.1016/S0140-1963(03)00121-6, 2004.
Fay, P. A., Carlisle, J. D., Knapp, A. K., Blair, J. M., and Collins, S. L.: Altering rainfall timing and quantity in a mesic grassland ecosystem: design and performance of rainfall manipulation shelters, Ecosystems, 3, 308–319, https://doi.org/10.1007/s100210000028, 2000.
Fensholt, R. and Kjeld, R.: Analysis of trends in the Sahelian “rain-use efficiency” using GIMMS NDVI, RFE and GPCP rainfall data, Remote Sens. Environ., 115, 438–451, https://doi.org/10.1016/j.rse.2010.09.014, 2011.
Fensholt, R., Rasmussen, K., Kaspersen, P., Huber, S., Horion, S., and Swinnen, E.: Assessing land degradation/recovery in the African Sahel from long-term earth observation based primary productivity and precipitation relationships, Remote Sensing, 5, 664–686, https://doi.org/10.3390/rs5020664, 2013.
Fensholt, R., Horion, S., Tagesson, T., Ehammer, A., Grogan, K., Tian, F., Huber, S., Verbesselt, J., Prince, S. P., Tucker, C. J., and Rasmussen, K.: Assessment of Vegetation Trends in Drylands from Time Series of Earth Observation Data, Remote Sensing Time Series, 22, 159–182, 2015.
Field, C.: Managing the risks of extreme events and disasters to advance climate change adaptation, IPCC Special Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, UK and New York, NY, USA, 582 pp., 2012.
Fischer, E. M., Beyerle, U., and Knutti, R.: Robust spatially aggregated projections of climate extremes, Nat. Clim. Change, 3, 1033–1038, https://doi.org/10.1038/nclimate2051, 2013.
Fitzpatrick, R. G. J., Bain, C. L., Knippertz, P., Marsham, J. H., and Parker, D. J.: The West African monsoon onset: a concise comparison of definitions, J. Climate, 28, 8673–8694, https://doi.org/10.1175/JCLI-D-15-0265.1, 2015.
Funk, C., Peterson, P., Landsfeld, M., Pedreros, D., Verdin, J., Shukla, S., Husak, G., Rowland, J., Harrison, L., Hoell, A., and Michaelsen, J.: The climate hazards infrared precipitation with stations – a new environmental record for monitoring extremes, Sci. Data, 2, 150066, https://doi.org/10.1038/sdata.2015.66, 2015.
Guan, K., Good, S. P., Caylor, K. K., Sato, H., Wood, E. F., and Li, H.: Continental-scale impacts of intra-seasonal rainfall variability on simulated ecosystem responses in Africa, Biogeosciences, 11, 6939–6954, https://doi.org/10.5194/bg-11-6939-2014, 2014.
Herman, A., Kumar, V. B., Arkin, P. A., and Kousky, J. V.: Objectively determined 10-day African rainfall estimates created for famine early warning systems, Int. J. Remote Sens., 18, 2147–2159, https://doi.org/10.1080/014311697217800, 1997.
Herrmann, S. M., Anyamba, A., and Tucker, C. J.: Recent trends in vegetation dynamics in the African Sahel and their relationship to climate, Global Environ. Chang., 15, 394–404, https://doi.org/10.1016/j.gloenvcha.2005.08.004, 2005.
Houerou, H. Le: Rain use efficiency: a unifying concept in arid-land ecology, J. Arid Environ., 7, 213–247, 1984.
Huber, S., Fensholt, R., and Rasmussen, K.: Water availability as the driver of vegetation dynamics in the African Sahel from 1982 to 2007, Global Planet. Change, 76(3–4), 186–195, https://doi.org/10.1016/j.gloplacha.2011.01.006, 2011.
Jönsson, P. and Eklundh, L.: TIMESAT – a program for analyzing time-series of satellite sensor data, Comput. Geosci., 30, 833–845, 2004.
Kaspersen, P. S., Fensholt, R., and Huber, S.: A spatiotemporal analysis of climatic drivers for observed changes in Sahelian vegetation productivity (1982–2007), Int. J. Geophys., 2011, 1–14, https://doi.org/10.1155/2011/715321, 2011.list
Kharin, V. V., Zwiers, F. W., Zhang, X., and Hegerl, G. C.: Changes in temperature and precipitation extremes in the IPCC ensemble of global coupled model simulations, J. Climate, 20, 1419–1444, https://doi.org/10.1175/JCLI4066.1, 2007.
Lebel, T. and Ali, A.: Recent trends in the Central and Western Sahel rainfall regime (1990–2007), J. Hydrol., 375, 52–64, https://doi.org/10.1016/j.jhydrol.2008.11.030, 2009.
Leisinger, K. M. and Schmitt, K.: Survival in the Sahel: an Ecological and Developmental Challenge, International Service for National Agricultural Research (ISNAR), The Hague, The Netherlands, 1995.
Liebmann, B., Bladé, I., Kiladis, G. N., Carvalho, L. M. V, Senay, G. B., Allured, D., Leroux, S., and Funk, C.: Seasonality of African precipitation from 1996 to 2009, J. Climate, 25, 4304–4322, https://doi.org/10.1175/JCLI-D-11-00157.1, 2012.
Mbow, C., Fensholt, R., Rasmussen, K., and Diop, D.: Can vegetation productivity be derived from greenness in a semi-arid environment? Evidence from ground-based measurements, J. Arid Environ., 97, 56–65, https://doi.org/10.1016/j.jaridenv.2013.05.011, 2013.
Muggeo, V. M. R.: Estimating regression models with unknown break-points, Stat. Med., 22, 3055–3071, https://doi.org/10.1002/sim.1545, 2003.
Nicholson, S. E.: The nature of rainfall variability over Africa on time scales of decades to millenia, Global Planet. Change, 26(1–3), 137–158, https://doi.org/10.1016/S0921-8181(00)00040-0, 2000.
Olsson, L., Eklundh, L., and Ardö, J.: A recent greening of the Sahel – trends, patterns and potential causes, J. Arid Environ., 63, 556–566, https://doi.org/10.1016/j.jaridenv.2005.03.008, 2005.
Panthou, G., Vischel, T., and Lebel, T.: Recent trends in the regime of extreme rainfall in the Central Sahel, Int. J. Climatol., 34, 3998–4006, https://doi.org/10.1002/joc.3984, 2014.
Penning de Vries, F. W. T. and Djiteye, M. A.: The Productivity of Sahelian Rangeland: a Study of Soils, Vegetation and the Exploitation of This Natural Resource, Centre for Agricultural Publishing and Documentation, Wageningen, Netherlands, 1982.
Prince, S., Colstoun, D., and Brown, E.: Evidence from rain-use efficiencies does not indicate extensive Sahelian desertification, Glob. Change Biol., 4, 359–374, https://doi.org/10.1046/j.1365-2486.1998.00158.x, 1998.
Proud, S. R. and Rasmussen, L. V.: The influence of seasonal rainfall upon Sahel vegetation, Remote Sens. Lett., 2, 241–249, https://doi.org/10.1080/01431161.2010.515268, 2011.
Ratzmann, G., Gangkofner, U., Tietjen, B., and Fensholt, R.: Dryland vegetation functional response to altered rainfall amounts and variability derived from satellite time series data, Remote Sensing, 8, 1026, https://doi.org/10.3390/rs8121026, 2016.
Rishmawi, K., Prince, S., and Xue, Y.: Vegetation responses to climate variability in the northern arid to sub-humid zones of Sub-Saharan Africa, Remote Sensing, 8, 910, https://doi.org/10.3390/rs8110910, 2016.
R Team: R: a language and environment for statistical computing. Vienna, Austria: R Foundation for Statistical Computing, available at: http://www.R-project.org/ (last access: 5 May 2017), 2014.
Romankiewicz, C., Doevenspeck, M., Brandt, M., and Samimi, C.: Adaptation as by-product: migration and environmental change in Nguith, Senegal, J. Geogr. Soc. Berlin, 147, 95–108, https://doi.org/10.12854/erde-147-7, 2016.
Sanogo, S., Fink, A. H., Omotosho, J. A., Ba, A., Redl, R., and Ermert, V.: Spatio-temporal characteristics of the recent rainfall recovery in West Africa, Int. J. Climatol., 35, 4589–4605, https://doi.org/10.1002/joc.4309, 2015.
Smith, M. D.: The ecological role of climate extremes: current understanding and future prospects, J. Ecol., 99, 651–655, https://doi.org/10.1111/j.1365-2745.2011.01833.x, 2011.
Taylor, C. M., Belušić, D., Guichard, F., Parker, D. J., Vischel, T., Bock, O., Harris, P. P., Janicot, S., Klein, C., and Panthou, G.: Frequency of extreme Sahelian storms tripled since 1982 in satellite observations, Nature, 544, 475–478, https://doi.org/10.1038/nature22069, 2017.
Thomey, M. L., Collins, S. L., Vargas, R., Johnson, J. E., Brown, R. F., Natvig, D. O., and Friggens, M. T.: Effect of precipitation variability on net primary production and soil respiration in a Chihuahuan Desert grassland, Glob. Change Biol., 17, 1505–1515, https://doi.org/10.1111/j.1365-2486.2010.02363.x, 2011.
Wessels, K., Prince, S., Malherbe, J., and Small, J.: Can human-induced land degradation be distinguished from the effects of rainfall variability? A case study in South Africa, J. Arid Environ., 68, 271–297, https://doi.org/10.1016/j.jaridenv.2006.05.015, 2007.
Wood, S.: Package mgcv, https://cran.r-project.org/web/packages/mgcv/index.html (last access: 1 September 2017), 2017.
Zhang, W., Brandt, M., Guichard, F., Tian, Q., and Fensholt, R.: Using long-term daily satellite based rainfall data (1983–2015) to analyze spatio-temporal changes in the sahelian rainfall regime, J. Hydrol., 550, 427–440, https://doi.org/10.1016/j.jhydrol.2017.05.033, 2017.