Decisive Atmospheric Circulation Indices for July–August Precipitation in North China Based on Tree ModelsSource: Journal of Hydrometeorology:;2019:;volume 020:;issue 008::page 1707DOI: 10.1175/JHM-D-19-0045.1Publisher: American Meteorological Society
Abstract: AbstractNumerous circulation indices have been applied in practical climate services focused on regional precipitation. It is beneficial to identify the most influential or decisive indices, but this is difficult with conventional correlation analyses because of the underlying nonlinear mechanisms for precipitation. This paper demonstrates a set of the most influential indices for July?August precipitation in North China, based on the recursive random forest (RRF) method. These decisive circulation indices include the Polar?Eurasia teleconnection, North African subtropical high ridge position, India?Burma trough, Antarctic Oscillation, Northern Hemisphere polar vortex central latitude, North Atlantic Oscillation, and western Pacific subtropical high northern boundary position. Some of these factors have been recognized as directly influential to the regional precipitation, for example, those of the northwestern Pacific subtropical high; however, some are not easily understood. Decision tree (DT) models using these indices were developed to facilitate composite analyses to explain the RRF results. Taking one of the most interesting DT rules as an example, when the North African subtropical high ridge position is sufficiently far south, an anomalous anticyclone occurs in the upstream and an anomalous cyclone in the downstream of North China. This is unfavorable for northward moisture transport in eastern China and hence causes less precipitation in North China than climatology. The present results are not only helpful for improving diagnostic models of regional precipitation, but also enlightening for exploring how global climate change could impact a region by modulating large-scale circulation patterns.
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contributor author | Tong, Xuan | |
contributor author | Yan, Zhongwei | |
contributor author | Xia, Jiangjiang | |
contributor author | Lou, Xiao | |
date accessioned | 2019-10-05T06:56:31Z | |
date available | 2019-10-05T06:56:31Z | |
date copyright | 7/2/2019 12:00:00 AM | |
date issued | 2019 | |
identifier other | JHM-D-19-0045.1.pdf | |
identifier uri | http://yetl.yabesh.ir/yetl1/handle/yetl/4263901 | |
description abstract | AbstractNumerous circulation indices have been applied in practical climate services focused on regional precipitation. It is beneficial to identify the most influential or decisive indices, but this is difficult with conventional correlation analyses because of the underlying nonlinear mechanisms for precipitation. This paper demonstrates a set of the most influential indices for July?August precipitation in North China, based on the recursive random forest (RRF) method. These decisive circulation indices include the Polar?Eurasia teleconnection, North African subtropical high ridge position, India?Burma trough, Antarctic Oscillation, Northern Hemisphere polar vortex central latitude, North Atlantic Oscillation, and western Pacific subtropical high northern boundary position. Some of these factors have been recognized as directly influential to the regional precipitation, for example, those of the northwestern Pacific subtropical high; however, some are not easily understood. Decision tree (DT) models using these indices were developed to facilitate composite analyses to explain the RRF results. Taking one of the most interesting DT rules as an example, when the North African subtropical high ridge position is sufficiently far south, an anomalous anticyclone occurs in the upstream and an anomalous cyclone in the downstream of North China. This is unfavorable for northward moisture transport in eastern China and hence causes less precipitation in North China than climatology. The present results are not only helpful for improving diagnostic models of regional precipitation, but also enlightening for exploring how global climate change could impact a region by modulating large-scale circulation patterns. | |
publisher | American Meteorological Society | |
title | Decisive Atmospheric Circulation Indices for July–August Precipitation in North China Based on Tree Models | |
type | Journal Paper | |
journal volume | 20 | |
journal issue | 8 | |
journal title | Journal of Hydrometeorology | |
identifier doi | 10.1175/JHM-D-19-0045.1 | |
journal fristpage | 1707 | |
journal lastpage | 1720 | |
tree | Journal of Hydrometeorology:;2019:;volume 020:;issue 008 | |
contenttype | Fulltext |