Moisture Balance for Bidecadal Variability of Wintertime Precipitation in the North Pacific Using NCEP/NCAR Reanalysis
Moisture Balance for Bidecadal Variability of Wintertime Precipitation in the North Pacific Using NCEP/NCAR Reanalysis
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DOI：
10.2151/jmsj.83.453
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发表时间：
2005-08
影响因子：
3.1
通讯作者：
T. Nakanowatari;S. Minobe
中科院分区：
文献类型：
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作者：
T. Nakanowatari;S. Minobe
利用美国国家环境预报中心/美国国家大气研究中心（NCEP/NCAR）的再分析资料，对Minobe和Nakanowatari（2002）报道的北太平洋降水中的双十年振荡（BDO）进行了水分收支分析。冬季降水中的BDO主要与水汽通量辐合有关，蒸发的贡献较小。水汽辐合主要是由于风和水汽在时间尺度上的异常超过一个月，除了在高纬度地区的瞬变涡（时间尺度短于一个月）的贡献更大。当阿留申低压加强（减弱）时，水汽通量的异常辐合是由30°-60d/南方涛动（ENSO）的气旋（反气旋）风环流引起的。0° ~ 30 ° N的异常环流与热带（20°S ~ 20°N）海平面气压异常有关，这一结果得到了国际综合海洋大气资料集（ICOADS）和NCEP实时海洋资料的证实。这种低纬异常环流在夏威夷降水变率的年代际和年际时间尺度上起着主导作用。
Moisture budgets are analyzed using National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis data over the North Pacific for a Bi-Decadal Oscillation (BDO) in precipitation that was reported by Minobe and Nakanowatari (2002). BDO in wintertime precipitation is mostly associated with moisture flux convergence, with a minor contribution from evaporation. The moisture convergence is mainly due to anomalies of wind and moisture on time scales longer than a month, except at high-latitudes where transient eddy (time scales shorter than a month) contributions are greater. When the Aleutian low strengthens (weakens), the anomalous moisture flux convergence is due to a cyclonic (anti-cyclonic) wind circulation over 30°-60d/Southern Oscillation (ENSO). The anomalous circulation over 0°-30°N is associated with sea-level pressure anomalies in the tropics (20°S-20°N) and this result is confirmed with the International Comprehensive Ocean-Atmosphere Data Set (ICOADS) and the NCEP real-time marine data. This low-latitude anomalous circulation plays a dominant role in precipitation variability in Hawaii on the bi-decadal and interannual time scales.