基于BCC-CSM2-MR模式CMIP6试验的辽河流域气温降水模拟与预估

基于国家气候中心中等分辨率模式版本BCC-CSM2-MR开展的第六次耦合模式比较计划(CMIP6)模拟结果, 首先利用辽河流域80个气象站点观测资料对模式的性能进行了评估, 然后分析了未来不同共享社会经济路径(SSP)情景下的气温降水变化趋势。结果表明: 模式能较好的模拟气温和降水的月、季、年变化, 模拟的气温较观测气温偏低, 模拟的降水略偏多; 模式对秋季和冬季气温的模拟性能明显优于夏季和春季, 对夏季降水的模拟性能较好。模式较好地模拟了辽河流域气温南高北低的纬向分布以及降水自东南向西北逐渐减少的空间分布形势, 较好地模拟出辽河流域冷暖中心位置, 模拟的降水偏少地区位于辽河流域水系稀疏地区。相对于基准期(1995—2014年), 未来辽河流域气温、降水基本呈增加趋势, 未来不同时期不同情景气温增幅均表现为平均最低气温>平均气温>平均最高气温, 冬季和春季增温幅度较大, 夏季降水量增幅最显著。随着排放情景升高, 平均气温和平均最低(最高)气温增幅持续增大, 显著增温地区集中于辽河流域东北部。SSP1-2.6和SSP2-4.5情景下预估降水的增幅自西南向东北递减, 降水增加大值区位于辽宁西部; SSP3-7.0和SSP5-8.5情景下降水增幅自西向东逐渐递减, 降水增幅显著区域位于辽河流域上游的内蒙古和辽宁西部。

Evaluation and projection of temperature and precipitation change in the Liaohe River Basin based on BCC-CSM2-MR model CMIP6 test

Based on the simulation results from the Coupled Model Intercomparison Project Phase Sixth (CMIP6) carried out by the medium resolution climate model BCC-CSM-MR from National Climate Center, we first evaluated the simulation capability of the model using the data from 80 meteorological stations in the Liaohe River Basin.Then we analyzed the trends of temperature and precipitation under the Shared Social-Economic Pathways (SSPs) in the future.The results show that the model can well simulate the monthly, seasonal, and annual variations of temperature and precipitation.The simulated temperature is lower than the observations, while the simulated precipitation is slightly overestimated.The simulation performances of temperature are significantly better in autumn and winter than in summer and spring, and those of precipitation are better in summer than in other seasons.The model well reproduces the zonal temperature variations of high in the south and low in the north, and the spatial variations of precipitation gradually decrease from southeast to northwest.The model also simulates well the location of the warm and cold center in the Liaohe River Basin, and the simulated areas with less precipitation are located in the sparse water system areas.Compared with the base period (1995-2014), the temperature and precipitation in the Liaohe River Basin will generally increase in the future, and the increase in various future scenarios from high to low is average minimum temperature, average temperature, and average maximum temperature, respectively.The temperature increase appears more significant in winter and spring, whereas the precipitation increase appears more significant in summer.With the increase in emission scenario, the average temperature and average minimum/maximum temperature increase continuously, and the significant warming areas are concentrated in the northeast of Liaohe River Basin.Under the SSP1-2.6 and SSP2-4.5 scenarios, the increase in precipitation is estimated to decrease from southwest to northeast, and the area with a large precipitation increase is located in the west of Liaoning province.Under the SSP3-7.0 and SSP5-8.5 scenarios, the increase in precipitation presents a meridional distribution with gradual decreases from west to east, and the significant precipitation increase areas are located in Inner Mongolia and western Liaoning province in the upper reaches of the Liaohe River Basin.