The Mesoscale Heavy Rainfall Observing System (MHROS) over the middle region of the Yangtze River in China

Abstract

The Mesoscale Heavy Rainfall Observing System (MHROS), supported by the Institute of Heavy Rain (IHR), Chinese Meteorology Administration, is one of the major systems to observe mesoscale convective systems (MCSs) over the middle region of the Yangtze River in China. The IHR MHROS consists of mobile C-POL and X-POL precipitation radars, millimeter wavelength cloud radar, fixed S-band precipitation radars, GPS network, microwave radiometers, radio soundings, wind profiler radars, and disdrometers. The atmospheric variables observed or retrieved by these instruments include the profiles of atmospheric temperature, moisture, wind speed and direction, vertical structures of MCS clouds and precipitation, atmospheric water vapor, and cloud liquid water. These quality-controlled observations and retrievals have been used in mesoscale numerical weather prediction to improve the accuracy of weather forecasting and MCS research since 2007. These long-term observations have provided the most comprehensive data sets for researchers to investigate the formation-dissipation processes of MCSs and for modelers to improve their simulations of MCSs. As the first paper of a series, we briefly introduce the IHR MHROS and describe the specifications of its major instruments. Then, we provide an integrative analysis of the IHR MHROS observations for a heavy rain case on 3-5 July 2014 as well as the application of IHR MHROS observations in improving the model simulations. In a series of papers, we will tentatively answer several key scientific questions related to the MCS and Meiyu frontal systems over the middle region of the Yangtze River using the IHR MHROS observations.

Vertical Structures of Typical Meiyu Precipitation Events Retrieved From GPM‐DPR

“…Generally, the rainband is characterized by a stepwise poleward movement from south China to north China (Ding, 1992;Lau et al, 1988;Lau & Yang, 1996). Heavy rain events often lead to local flooding and debris flows that can cause severe property damage and loss of life (Cui et al, 2015;Gao et al, 2016). Within this rainband, mesoscale convective systems (MCSs) develop successively and thus trigger local heavy rainfall (Ding & Chan, 2005;Yu & Li, 2012).…”

“…Within this rainband, mesoscale convective systems (MCSs) develop successively and thus trigger local heavy rainfall (Ding & Chan, 2005;Yu & Li, 2012). Heavy rain events often lead to local flooding and debris flows that can cause severe property damage and loss of life (Cui et al, 2015;Gao et al, 2016). Accurate forecasting of Meiyu rain is crucial to avoid such natural disasters.…”

Contrasting Pre-Mei-Yu and Mei-Yu Extreme Precipitation in the Yangtze River Valley: Influencing Systems and Precipitation Mechanisms

“…The mei-yu season over the Yangtze-Huai Rivers basin, typically occurring from mid-June to mid-July, is one of three heavy-rainfall periods over China (Ding 1992;Luo et al 2014;Cui et al 2015). In some years, mei-yu precipitation can contribute 50% of the annual precipitation (Liu and Wang 2006).…”

“…To the north side of the front, the northwesterly flow dominates, carrying much cooler air from northern China. The low-level convergence enhances lifting, resulting in a narrow band of convection on the warm side (south side) of the front (Lin et al 1992;Cui et al 2015).…”

“…Rainstorms during the mei-yu period are usually formed under certain favorable environmental conditions, such as the interaction of multiple scales of systems (Ninomiya and Akiyama1992;Ni 2001;Zhang et al 2002;Cui et al 2015). Zhang and Tao (1998) found that precipitation anomalies during the mei-yu period are closely related to the establishment of blocking patterns in the middle and high latitudes, which affect precipitation by modulating the southward invasion of cold air masses.…”