The Development and Evolution of Two Atmospheric Rivers in Proximity to Western North Pacific Tropical Cyclones in October 2010
The Development and Evolution of Two Atmospheric Rivers in Proximity to Western North Pacific Tropical Cyclones in October 2010
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DOI：
10.1175/mwr-d-13-00019.1
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发表时间：
2013-12-01
影响因子：
3.2
通讯作者：
Moore, Benjamin J.
中科院分区：
文献类型：
--
作者：
Cordeira, Jason M.;Ralph, F. Martin;Moore, Benjamin J.
本研究调查了2010年10月下旬在北方加州山区产生>200 mm降雨的两条带状细长大气河流（AR）的演变。天气尺度分析和气包轨迹分析表明，ARs的发展在高CAPE环境的特点是对流层深上升的水汽直接从西北太平洋热带气旋（TC）向赤道入口区的增强北太平洋急流（NPJ）输送。同样的AR随后保持从温带和副热带地区的水汽输送到中东部北太平洋的准地转强迫上升和强烈的锋生沿着的反气旋切变侧的强烈和纬向延伸的NPJ的环境特征。虽然发展的AR与水汽输送从TC附近的地区，并在对流层深上升的存在下，大气中的水汽收支表明，通过降水减少的综合水汽（IWV）在很大程度上抵消了水汽的水平聚集沿着AR走廊通过IWV通量辐合在锋生的存在。用于调查的前身雨事件之前的TC和反弯TC和NPJ之间的相互作用的框架也被用来说明许多动态相似的过程相关的AR的发展和演变。相似之处包括：直接从TC，对流层深上升的高CAPE环境下的赤道入口区域的加强对流层上层急流条纹，非绝热外流和对流层上层急流条纹之间的相互作用，强锋生的水汽输送。
This study investigates the evolution of two zonally elongated atmospheric rivers (ARs) that produced >200 mm of rainfall over mountainous regions of Northern California in late October 2010. Synoptic-scale analysis and air parcel trajectory analysis indicate that the ARs developed within high-CAPE environments characterized by troposphere-deep ascent as water vapor was transported directly from western North Pacific tropical cyclones (TCs) toward the equatorward entrance region of an intensifying North Pacific jet stream (NPJ). The same ARs were subsequently maintained as water vapor was transported from extratropical and subtropical regions over the central and eastern North Pacific in an environment characterized by quasigeostrophic forcing for ascent and strong frontogenesis along the anticyclonic shear side of an intense and zonally extended NPJ. Although the ARs developed in conjunction with water vapor transported from regions near TCs and in the presence of troposphere-deep ascent, an atmospheric water vapor budget illustrates that decreases in integrated water vapor (IWV) via precipitation are largely offset by the horizontal aggregation of water vapor along the AR corridors via IWV flux convergence in the presence of frontogenesis. The frameworks used for investigations of predecessor rain events ahead of TCs and of interactions between recurving TCs and the NPJ are also utilized to illustrate many dynamically similar processes related to AR development and evolution. Similarities include the following: water vapor transport directly from a TC, troposphere-deep ascent in a high-CAPE environment beneath the equatorward entrance region of an intensifying upper-tropospheric jet streak, interactions between diabatic outflow and an upper-tropospheric jet streak, and strong frontogenesis.