Climate change projections over China using regional climate models forced by two CMIP5 global models. Part II: projections of future climate

Abstract

The changes in mean and extreme climate in China during 2020–2060 are detected with both Weather Research and Forecasting and RegCM4, by downscaling the simulations from EC‐EATTH and IPSL‐CM5A under both the RCP4.5 and RCP8.5 scenarios. The climate changes under the two scenarios exhibit similar patterns, with stronger intensity under the RCP8.5 scenario. For the mean precipitation, increases are projected in most regions, with the largest relative increase in the Tarim Basin. Slight drought mainly occurs in the south‐eastern part of China. The frequency of drizzle rain is expected to decrease in all the sub‐regions, but the moderate to heavy rainfall as well as the storm would occur more frequently, especially on the Tibetan Plateau. The whole country would experience much warmer climate in the future, with the strongest warming over the Tibetan Plateau. By detecting the changes in climate extremes, it is indicated that less dry extremes would occur in the wet areas of China, while more dry events in the arid and semiarid regions. The wet extreme indices would increase in most regions, especially in the wet areas. The surface air temperature tends to become extremely warmer in the future over the whole country, with the strongest change over the Tibetan Plateau. The changes in mean and extreme climate depend strongly on the driving global climate models, with wetter and warmer climate in the downscalings over IPSL‐CM5A, and the model physics of the regional climate models also exert great impact on the projections. Finally, the possible mechanisms for the changes of extreme precipitation are discussed. The enhanced summer monsoon in the future transports more moisture to China, which could lead to more summer precipitation. As a result, the wet extremes tend to increase.

Survival of the Qaidam mega-lake system under mid-Pliocene climates and its restoration under future climates

“…Since the mid-Pliocene is often regarded as a past analogue for modern climate changes (Zubakov and Borzenkova, 1988;Haywood et al, 2016;Chandan and Peltier, 2018), this study also intends to provide a rational basis for assessing environmental changes that might be caused by climate changes as projected in this region for the future (Burke et al, 2018;Gu et al, 2018;Hui et al, 2018).…”

Survival of the Qaidam Mega-Lake System under Mid-Pliocene Climates and its Restoration under Future Climates

“…Table 2 presents estimates for mean annual changes in the water balance of the Qaidam basin due to climate changes with respect to present conditions. The first three rows (marked in red) indicate changes in q, P, and ΔS = P -ET for estimates of minimum and maximum changes in T. As conservative estimates, the minimum and maximum changes in air temperature were set to 1 K and 2 K, respectively, which can be used as estimates for the air temperature range representing both mid-Pliocene climates and those projected for the end of the 21st century (Burke et al, 2018;Gu et al, 2018;Hui et al, 2018).…”

“…Global climate change as projected for the future and its consequences for the regional climates of China (Burke et al, 2018;Gu et al, 2018;Hui et al, 2018) could lead to strengthening of the East Asian Summer Monsoon (Wang et al, 2008), which could also affect the Qaidam basin such that both specific humidity and precipitation would increase. This would then lead to continued recharge of groundwater reservoirs and, at a later stage, to rising lake levels or formation of new lakes.…”

“…Moreover, a physically based explanation for the longterm existence of the mega-lake system under dry climate conditions is sought. Since the mid-Pliocene is often regarded as past analogue for modern climate changes (Zubakov and Borzenkova, 1988;Haywood et al, 2016), this study also intends to provide a rational basis for assessing environmental changes that might be caused by climate changes as projected in this region for the future (Burke et al, 2018;Gu et al, 2018;Hui et al, 2018).…”

Impact of future land use and land cover change on temperature projections over East Asia

“…The Community Land Model version 3.5 (CLM; Oleson et al 2008) is adopted for the land surface model, with 15 plant functional types (PFT), bare ground, lakes and glaciers (Dai et al 2003). The lateral boundary conditions (LBCs) affect not only the simulation of climatic conditions (Niu et al 2015;Hui et al 2018) but also the simulated climate change signals (Yu and Wang 2014;Saini et al 2015). Considering that the climate responses to LULCC in RCM simulations may depend on the LBCs, we choose two GCMs, including the Institute Pierre Simon Laplace-Climate Model version 5A (IPSL-CM5A) (Dufresne et al 2013) and EC-EARTH (Hazeleger et al 2010), to provide the initial and LBCs for RegCM4 in this study.…”