Modeled responses of summer climate to realistic land use/cover changes from the 1980s to the 2000s over eastern China

Abstract

Eastern China has experienced substantial agricultural expansion and deforestation in recent decades. We modeled the influence of land use/cover changes (LUCCs) over eastern China on the regional climate using the Weather Research and Forecasting model with the Noah-multiparameterization land surface scheme. Two 21 year experiments were performed using the same settings, except for the land use/cover data for the 1980s and the 2000s. The results showed that in northern China, decreases in the surface air temperature of approximately 0.3-0.5°C and decreases (increases) in rainfall over the lower reaches of the Yangtze River valley (southern China, northeastern China, and the Korean Peninsula) of approximately 3% (6-7%) in the summer were associated with LUCCs in eastern China from the 1980s to the 2000s. The cooling effect in northern China, which was primarily attributable to an increase in the surface latent heat flux of approximately 7.3-9.6 W m À2, weakened the land-ocean thermal contrast, suggesting the presence of a weaker summer monsoon over eastern China. As a result, rainfall over the lower reaches of the Yangtze River valley (southern China) tended to decrease (increase). In addition, the cooling effect may have produced an anomalous cyclonic circulation from the surface to the midtroposphere over northeastern China and the Korean Peninsula, resulting in increased rainfall over this area.

Modeled effects of irrigation on surface climate in the Heihe River Basin, Northwest China

“…Following the method described by Y. Hu et al . [], we transferred the 1 km resolved land use data for 2010 with land use categories into the more coarsely (3 km) resolved grid used in WRF/Noah‐MP model simulations, using the USGS land cover categories. The updated land use data are shown in Figure .…”

Spatial Variability of Wet Troposphere Delays Over Inland Water Bodies

“…The WRF 11.33 km grid cell (second nest) closest to the SGP‐ARM observation site is located at 36.462°N, 97.523°W, which is ~6 km northwest of the SGP‐ARM central facility (Figure ). With the exception of some downward bias in ZWD during summer (June‐July‐August (JJA)) (Hu et al, ; Jin et al, ), WRF generally reproduces the seasonal cycle and variability of ZWD as measured at the SGP‐ARM site (see Figures a1 and a2, which show WRF results for the pixel closest to the SGP‐ARM site). We also compared our WRF‐derived ZWD over the case study sites with GPS‐derived ZWD locations in both 1999 and 2016 that were within our domain (as for SGP‐ARM, none were within our inner nest, but several are within the 11 km nest) Figures b1 and b2 for Elephant Butte, Figures c1 and c2 for Ray Hubbard, and Figures d1 and d2 for Sam Rayburn compare the ZWD estimates.…”

Temperature changes in Three Gorges Reservoir Area and linkage with Three Gorges Project

“…Similar to the mechanism in the water impounding region, the cooling (warming) effects were driven by two competing biophysical effects: ET and albedo. In the subtropical region where TGRA located, the increase in vegetation generally resulted in surface cooling during the summer because the stronger evaporative cooling offsets the albedo warming [ Betts et al , ; Bonan , ; Hu et al , ; Jeong et al , ; Li et al , ; Peng et al , ]. Thus, ecological protection projects appear to be another factor that has led to temperature changes along the TGR.…”

“…In the subtropical region where TGRA located, the increase in vegetation generally resulted in surface cooling during the summer because the stronger evaporative cooling offsets the albedo warming [Betts et al, 2007;Bonan, 2008;Hu et al, 2015;Jeong et al, 2009;Li et al, 2015;Peng et al, 2014]. Thus, ecological protection projects appear to be another factor that has led to temperature changes along the TGR.…”