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This study presented a detailed comparison of daily
precipitation estimates from Precipitation Estimation from
Remote Sensing Information using Artificial Neural Network
(PERSIANN) and Tropical Rainfall Measuring Mission (TRMM) Multi
-satellite Precipitation Analysis (TMPA) over Hunan province of
China from 1998 to 2014. The ground gauge observations are taken
as the reference. It is found that overall TMPA clearly
outperforms PERSIANN, indicating by better statistical metrics
(including correlation coefficient, root mean square error and
relative bias). For the geospatial pattern, although both
products are able to capture the major precipitation features
(e.g., precipitation geospatial homogeneity) in Hunan, yet
PERSIANN largely underestimates the precipitation intensity
throughout all seasons. In contrast, there is no clear bias
tendency from TMPA estimates. Precipitation intensity analysis
showed that both the occurrence and amount histograms from TMPA
are closer to the gauge observations from spring to autumn.
However, in the winter season PERSIANN is closer to gauge
observation, which is likely due to the ground contamination
from the passive microwave sensors used by TMPA. 相似文献
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海温异常对西太平洋副热带高压脊面演变影响的机制研究 总被引:1,自引:0,他引:1
根据欧洲中期数值预报中心提供的大气环流资料和NOAA提供的海温资料, 应用改进的低阶谱模式方法研究了海温异常对西太平洋副热带高压脊面演变影响的物理机制. 结果表明, 在El Niño型海温强迫下, 大气环流内部动力过程中的大尺度波波和波流相互作用较弱. 随着外部热源强迫从冬季型向夏季型推进, 西太平洋副热带高压脊面北进不明显, 使得夏季西太平洋副热带高压脊面相对偏南. 在La Niña型海温强迫下, 大气环流内部动力过程中的大尺度波波和波流相互作用明显. 随着外源强迫从冬季型向夏季型转变, 西太平洋副热带高压脊面将随之向北移动19个纬度左右, 使得夏季西太平洋副热带高压脊面偏北; 且北移到达一定纬度后, 西太平洋副热带高压脊面表现出较为显著的30~60 d季节内南北振荡, 振幅在4°~7°之间.不同海温异常型所导致的大气内部动力过程差异是造成西太平洋副热带高压脊面年际变化的重要原因之一. 相似文献
3.
利用谱分析、带通滤波、奇异值分解及合成分析等方法,以及欧洲中期数值天气预报中心大气环流再分析资料和美国NOAA的海温资料,研究了夏季西太平洋副热带高压(下称西太副高)脊面年际变化及其对前期太平洋海温响应的物理过程.结果表明,西太副高脊面存在准7.5年的最显著振荡周期.太平洋前冬和前春海温对夏季西太副高脊面的影响是显著的.其中El Ni(n)o型的异常海温分布将使夏季两太副高脊面偏南,而La Ni(n)a型的则使夏季西太副高脊面偏北.在对比分析与太平洋海温异常相联系的异常环流的基础上,发现异常海温强迫出的异常经向环流是有利于夏季西太副高脊面异常的一个重要原因. 相似文献
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