Subseasonal prediction performance for South American land-atmosphere coupling in extended austral summer
Subseasonal prediction performance for South American land-atmosphere coupling in extended austral summer
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南美洲夏季延长期间南美陆地-大气耦合的次季节预测性能
DOI：
10.1002/cli2.28
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Chevuturi A
中科院分区：
文献类型：
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作者：
Chevuturi A
通过水和能量交换，陆地-大气反馈提供了水文循环的次季节到季节的可预测性。我们分析了南美洲（SA）在延长的南半球夏季期间的次季节陆地-大气耦合，以了解土壤湿度与降水和土壤湿度与空气温度的反馈路径。我们根据两次重新分析，评估了英国气象局、国家环境预测中心 (NCEP)、欧洲中期天气预报中心和天气预报和气候研究中心 (CPTEC) 的全球预报系统在 1999 年至 2010 年期间的次季节后报。陆地-大气状态的偏差在后报的第一周就确定了，并随着提前时间的推移而增加。到第 5 周，所有模型仅在南澳北部、东北部和东南部的土壤湿度和蒸散量以及热带和亚热带南澳的温度方面表现出良好的性能。后报显示，与重新分析相比，变量之间的超前滞后时间更长，耦合更强。我们的结果强调了由于初始干燥土壤湿度偏差，亚马逊地区 CPTEC 和 NCEP 预测中土壤湿度和降水之间的反馈可能存在缺陷，以及由于蒸散量的错误表示而导致南澳东南部所有四个研究模型的土壤湿度和温度之间的反馈可能存在缺陷。
Land–atmosphere feedbacks, through water and energy exchanges, provide subseasonal‐to‐seasonal predictability of the hydrological cycle. We analyse subseasonal land–atmosphere coupling over South America (SA) during extended austral summer for the soil moisture‐to‐precipitation and soil moisture‐to‐air temperature feedback pathways. We evaluate subseasonal hindcasts from global forecasting systems from the UK Met Office, the National Centers for Environmental Prediction (NCEP), the European Centre for Medium Range Weather Forecasts and the Center for Weather Forecast and Climate Studies (CPTEC), for the common period of 1999–2010, against two reanalyses. Biases in land–atmosphere states are established in the first week of hindcasts and increase with lead time. By Week 5, all the models only demonstrate good performance over northern, northeastern and southeastern SA for soil moisture and evapotranspiration and over tropical and subtropical SA for temperature. The hindcasts show stronger coupling at longer lead–lag between variables than reanalyses. Our results highlight possible deficiencies in feedbacks between soil moisture and precipitation in CPTEC and NCEP forecasts over the Amazon due to initial dry soil moisture biases, and in feedbacks between soil moisture and temperature for all four investigated models over southeastern SA due to erroneous representations of evapotranspiration.