Subjects: Geosciences >> Atmospheric Sciences submitted time 2023-05-30 Cooperative journals: 《干旱区研究》
Abstract： The dominant sea surface temperature anomaly (SSTa) modes of decadal and interannual variations in summer precipitation over the eastern part of Northwest China (ENC) were here analyzed by power spectrum and composite analyses. The summer precipitation averaged at 155 stations over the ENC, the monthly SSTa, and circulation reanalysis data from 1961 to 2020 were used. The SSTa predictors before and after the timescale decomposition were obtained to establish precipitation prediction models by using linear regression. The results showed that the summer precipitation over the ENC has not only an decadal period of about 30 years but also a 3-year interannual cycle. The Pacific Decadal Oscillation (IPO) has played a leading role in decadal variations in summer precipitation. The positive phase of IPO in the precedent spring is conducive to more precipitation; meanwhile, it is in the background of less precipitation . The tropical Indian Ocean, the tropical western Pacific, and the North Atlantic provide interannual SSTa signals. The negative (positive) phase of tropical Indian Ocean SSTa, the positive (negative) phase of the Atlantic tripole SSTa, and the cold (warm) SSTa in the tropical western
Pacific Ocean in the precedent spring, corresponding to the high (low) pressure anomalies over Lake Balkhash in mid- to high latitudes, with northward (southward) and weak (strong) characteristics in the subtropical High over the Western Pacific, favor less (more) summer precipitation over the ENC. Moreover, taking the decadal and interannual variations of SSTa into account can potentially contribute to improving forecasting of summer precipitation over the ENC, with the annual average Ps and Pc scores during the independent test samples based on the scale decomposition model being 6% and 7% higher than those in the original model, respectively.
Subjects: Geosciences >> Geography submitted time 2020-06-02 Cooperative journals: 《干旱区地理》
Abstract： 利用宁夏全域5个地市1980-2018年逐日白昼气温、相对湿度、风速、日照时数等气象资料，运用温湿指数、风寒指数、着衣指数和综合舒适指数模型，计算出旅游气候适宜期天数，并对其变化趋势及变化原因进行分析。综合舒适指数模型结果表明:石嘴山、银川、吴忠、中卫4市的旅游气候适宜期较为一致，为3月10日一11月7日，持续时长为243 d。固原的旅游气候适宜期为3月27日一10月29日，持续时长为217 d;石嘴山、吴忠、中卫全年旅游适宜天数变化不显著，是由始期、终期适宜天数增加幅度与“凹”面期适宜天数的减少幅度相当所致。银川、固原全年旅游适宜天数显著增加，主要是始期、终期适宜天数增加幅度大于“凹”面期适宜天数的减少幅度所致;各地始期、终期适宜天数显著增加是由气温升高、相对湿度降低和其他要素的差异变化共同作用所致。“凹”面期适宜天数显著减少是由气温升高(高温日数增多),相对湿度降低和其他要素的差异变化共同作用所致;各地始期、终期、“凹”面期，气温的显著变化对适宜天数显著变化的影响权重最大，达到50%以上，相对湿度、风速、日照时数的影响权重各有差异。
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