|The authors addressed all my concerns and improved the manuscript substantially. Therefore, the manuscript could be published after minor revisions (mainly spell checking, and a thorough proof reading is necessary).|
L9-10: I still think that those variables do not fully describe the state of the biosphere, so it seems more accurate to write: account for 82% of the variance of the selected biosphere variables in space and time
L13: Rephrase ‘they also allow us’. What does they refer to (the anomalies, or the indicators/pcas)?
L19: add: Díaz, S., Settele, J., Brondizio, E. S., Ngo, H. T., Agard, J., Arneth, A., … Zayas, C. N. (2019). Pervasive human-driven decline of life on Earth points to the need for transformative change. Science, 1327(December). https://doi.org/10.1126/science.aaw3100
L41: what do you mean by qualitative state?
L49: decide whether to use ‘high-dimensional’ or ‘high dimensional’
L78: rephrase, maybe just simplify to ‘and analyses such as mean seasonal cycles …’
L99: for this study,
L102: available variables
L106: of analysis
L109: rephrase: Because the area of the pixel changes with latitude in the equirectangular coordinate system used by the ESDL
L142: remove ‘n’
L197: something is missing in this sentence
L202: Rephrase and clarify the first sentence. What type of dynamics are you referring to?
L216: Rephrase to be more readable (and add the section numbers accordingly): In the following, we first briefly present and discuss the quality of the global dimensionality reduction and interpret the individual components from an ecological point of view. We summarize the global dynamics that we uncovered in the low-dimensional space. We characterize the contained seasonal dynamics, including spatial patterns of hysteresis. … finally, we present global trends and their breakpoints.
Figure 2b) I agree that it makes sense to visualize the variable loadings to the PCs in this way, but it is still pretty hard to read the contributions for the first three components, because the values all lie close together at maybe around -0.5 to 0.5. Is there a way to rescale the colorbar/colormap (are the extremes of -1 and 1 even reached by the data range)? Or choose a colormap, which is more distinguishable at the lower values.
L241-246: Check spelling of that whole paragraph!
Figure 3: This figure could be improved: add titles for top, middle and bottom rows, don’t cut the top MSE distribution at 1.2, or maybe use log-scale if needed, and I think it would be ok to use different value ranges for each subfigure (b-d-f) to illustrate relative error distributions, since the color already indicates the absolute differences.
L263: Be more precise about the definition of albedo! See the following paper describing the differences between black-sky and white-sky albedo: Schaepman-Strub, G., Schaepman, M. E., Painter, T. H., Dangel, S., & Martonchik, J. V. (2006). Reflectance quantities in optical remote sensing-definitions and case studies. Remote Sensing of Environment, 103(1), 27–42. https://doi.org/10.1016/j.rse.2006.03.002
L265: can be caused by many reasons
L279/280: Check spelling!
L325: check spelling
L338: third component
L340-341: It is indeed hard to say what exactly PC3 represents, especially since the northern boreal forests should show a very low albedo, especially during summer. There are a few other aspects though, potentially related to bare soil albedo (using cover-crops vs bare soil in agricultural practices) and changing bare soil albedo due to soil wetness. So if there is a large soil fraction, PC2 and 3 could be related due to lower surface albedo of wet soils.
Figure 6: nice figure, but I would also optimize the color range of column two and three. There is only light colors, which indicates that a smaller range could show the patterns more clearly (e.g. just disregard extreme values when defining the color-range).
L355: It seems to track surface reflectance changes, which are not caused by vegetation phenology (since that is included in PC1). So maybe soil albedo plays a role too.
L395: instead of
L402 onwards: check spelling
L488 onwards: split into several sentances
L532: formed by
L553: three indicators
L553/554: the second … while the third
L566: Future research should consider non-linearities, adding data streams describing other important biosphere variables (e.g. related to biodiversity and habitat quality), and including different subsystems…