摘要
国际耦合模式比较计划第六阶段(CMIP6)新增的高分辨率模式比较计划(HighResMIP)首次提供全球高分辨率(25—50 km)多模式集合的气候模拟试验结果。利用8个CMIP6 HighResMIP模式评估了高分辨率全球气候模式对青藏高原夏季小时降水与极端降水的模拟能力,结果表明:CMIP6高分辨率模式高(低)估了青藏高原地区的降水量和频率(强度),过多的降水量主要来自模式对降水频率的高估,尤其是弱降水(<2 mm·h^(-1))的发生频率。模拟偏差与地形海拔密切相关,偏差大值区主要位于高原南坡和东坡陡峭地形区。模式不能准确再现降水量与海拔之间的关系,高(低)估了高(低)海拔地区的降水量。模式低估了降水强度随海拔升高而降低的变化速率。在日变化方面,模式能够模拟出青藏高原降水傍晚至午夜的峰值特征,但明显低估了降水的日变化振幅。在小时极端降水方面,模式低估了高原区域平均极端降水第95百分位数阈值,仅为观测值的57%。
High Resolution Model Intercomparison Project(HighResMIP)from the Coupled Model Intercomparison Project 6(CMIP6),for the first time,provides global high-resolution(25-50 km)multi-model ensemble simulations.Based on simulations of eight CMIP6 HighResMIP models,the performance of the state of the art global high-resolution models in simulating hourly precipitation and extreme pre⁃cipitation in summer over the Tibetan Plateau is evaluated.The results show that CMIP6 high-resolution models overestimate(underesti⁃mate)the precipitation amount and frequency(intensity).The positive bias of precipitation amount is mostly contributed by the overestimated frequency,especially the frequency of weak precipitation(<2 mm·h-1).The simulation deviations are closely related to terrain elevation,and the areas with large bias are mainly located in the steep terrain on the south and east slopes of the plateau.The models fail to accurately repro⁃duce the relationship between precipitation amount and elevation,with overestimation(underestimation)of the amount in high(low)-altitude areas.The models underestimate the rate of precipitation intensity decreasing with increasing elevation.In terms of diurnal variation,the mod⁃els can simulate the late-afternoon and midnight peaks of precipitation over the Tibetan Plateau,but obviously underestimates the diurnal am⁃plitude of precipitation.In terms of hourly extreme precipitation,the models underestimate the 95th percentile threshold of the area-average precipitation intensity in the plateau,which was only 57%of the observed value.
作者
肖雨佳
李建
李妮娜
XIAO Yujia;LI Jian;LI Nina(Chinese Academy of Meteorological Sciences,Beijing 100081;State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences,Beijing 100081;National Meteorological Centre,Beijing 100081)
出处
《暴雨灾害》
2022年第2期215-223,共9页
Torrential Rain and Disasters
基金
国家自然科学基金项目(91637210,41675075)。
