Spatially varying relevance of hydrometeorological hazards for vegetation productivity extremes

[摘要] Vegetation plays a vital role in the Earth system bysequestering carbon, producing food and oxygen, and providing evaporativecooling. Vegetation productivity extremes have multi-faceted implications,for example on crop yields or the atmospheric CO 2 concentration. Here, wefocus on productivity extremes as possible impacts of coinciding,potentially extreme hydrometeorological anomalies. Using monthly globalsatellite-based Sun-induced chlorophyll fluorescence data as a proxy forvegetation productivity from 2007–2015, we show that vegetationproductivity extremes are related to hydrometeorological hazards ascharacterized through ERA5-Land reanalysis data in approximately 50 % ofour global study area. For the latter, we are considering sufficientlyvegetated and cloud-free regions, and we refer to hydrometeorologicalhazards as water- or energy-related extremes inducing productivity extremes.The relevance of the different hazard types varies in space;temperature-related hazards dominate at higher latitudes with cold spellscontributing to productivity minima and heat waves supporting productivitymaxima, while water-related hazards are relevant in the (sub-)tropics withdroughts being associated with productivity minima and wet spells with themaxima. Alongside single hazards compound events such as joint droughtsand heat waves or joint wet and cold spells also play a role, particularly in dryand hot regions. Further, we detect regions where energy control transitionsto water control between maxima and minima of vegetation productivity.Therefore, these areas represent hotspots of land–atmosphere coupling wherevegetation efficiently translates soil moisture dynamics into surface fluxessuch that the land affects near-surface weather. Overall, our resultscontribute to pinpointing how potential future changes in temperature andprecipitation could propagate to shifting vegetation productivity extremesand related ecosystem services.

[学科分类] 大气科学