Vegetation masking effect on future warming and snow albedo feedback in a boreal forest region of northern Eurasia according to MIROC‐ESM

Abstract

The Earth system model, Model for Interdisciplinary Research on Climate‐Earth system model (MIROC‐ESM), in which the leaf area index (LAI) is calculated interactively with an ecological land model, simulated future changes in the snow water equivalent under the scenario of global warming. Using MIROC‐ESM, the effects of the snow albedo feedback (SAF) in a boreal forest region of northern Eurasia were examined under the possible climate future scenario RCP8.5. The simulated surface air temperature (SAT) in spring greatly increases across Siberia and the boreal forest region, whereas the snow cover decreases remarkably only in western Eurasia. The large increase in SAT across Siberia is attributed to strong SAF, which is caused by both the reduced snow‐covered fraction and the reduced surface albedo of the snow‐covered portion due to the vegetation masking effect in those grid cells. A comparison of the future changes with and without interactive LAI changes shows that in Siberia, the vegetation masking effect increases the spring SAF by about two or three times and enhances the spring warming by approximately 1.5 times. This implies that increases in vegetation biomass in the future are a potential contributing factor to warming trends and that further research on the vegetation masking effect is needed for reliable future projection.

Biophysical impacts of northern vegetation changes on seasonal warming patterns

“…Vegetation greening also affects climate by interacting with other land-surface (e.g., snow or soil moisture) and atmospheric (e.g., water vapor, cloud, and circulation) processes 11,13,18 , the effects of which vary both geographically and seasonally 4 . For example, during snowaffected seasons/areas, vegetation greening markedly decreases snow cover and surface albedo due to a strong masking effect of darker canopies 11,[18][19][20] , and the surface darkening would warm the surface that further accelerates snow losses 21,22 . In addition to affecting climate locally and transiently, vegetation biophysical processes summarized above can potentially trigger climate anomalies beyond the greening region (non-local feedbacks) and season (inter-seasonal feedbacks) [23][24][25] , by redistributing available energy over space and time.…”

Reconstruction of Historical Land Surface Albedo Changes in China From 850 to 2015 Using Land Use Harmonization Data and Albedo Look‐Up Maps

“…During the last 300 years, a large amount of land reclamation and deforestation occurred in NE as a result of the large‐scale “Chuang Guandong” (migration during the 19th and 20th centuries) (Yang et al., 2017), as well as land reclamation in Heilongjiang Province (the “Great Northern Wilderness”) during the mid‐20th century (Liu et al., 2014). Additionally, the increases of land surface albedo were enhanced by the vegetation masking effect on snow cover (Abe et al., 2017; Essery, 2013), which exhibited much stronger increasing trends over northern China. The most significant decreases in land surface albedo occurred in the central Songnen Plain, the farming‐pastoral ecotone of China, the Sichuan Basin, and the lower reaches of the Yangtze River.…”

“…It can be seen that the increase in land surface albedo of snow‐covered low stature vegetation (e.g., grasslands and croplands) was much larger than that of snow‐covered high stature vegetation (e.g., forests). When the land cover type was converted from forests to croplands, the fraction of snow exposure during wintertime increased (Abe et al., 2017; Essery, 2013), causing a negative radiative forcing. For example, the strong negative radiative forcing in Northeast China (NE) was primarily caused by land reclamation and deforestation (Ye et al., 2009), which cause snow cover during winter to have a higher fractional exposure area and longer duration.…”

Impact of snow‐albedo feedback termination on terrestrial surface climate at midhigh latitudes: Sensitivity experiments with an atmospheric general circulation model

“…Therefore, snow cover change likely contributes to global warming continually and significantly. Additionally, across northern continental areas, the SAF is likely to warm the regional SAT significantly (Fletcher et al ., 2012; Qu and Hall, 2014; Abe et al ., 2017). However, model estimates of SAF are accompanied by large uncertainties.…”