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OPERATIONAL forecast OF rainfall INDUCED BY LANDFALLING TROPICAL CYCLONES ALONG GUANGDONG COAST

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Journal of Tropical Meteorology 2020年第1期26卷 1-13页

作者： LI Qing-lan LIU Bing-rong WAN Qi-lin WANG Yu-qing LI Guang-xin LI Tie-jian LAN Hong-ping FENG Sheng-zhong LIU Chun-xia Shenzhen Institute of Advanced Technology Chinese Academy of SciencesShenzhenGuangdong 518055 China Guangzhou Institute of Tropical and Marine Meteorology CMAGuangzhou 510641 China University of Hawaii at Manoa HonoluluHI 96822 USA Department of Hydraulic Engineering Tsinghua UniversityBeijing 100084 China Shenzhen Meteorological Bureau ShenzhenGuangdong 518040 China

Following previous studies of the rainfall forecast in Shenzhen owing to landfalling tropical cyclones(TCs),a nonparametric statistical scheme based on the classification of the landfalling TCs is applied to analyze and forecast the rainfall induced by landfalling TCs in the coastal area of Guangdong province,*** the TCs landfalling with the distance less than 700 kilometers to the 8 coastal stations in Guangdong province during 1950—2013 are categorized according to their landfalling position and *** daily rainfall records of all the 8 meteorological stations are obtained and *** maximum daily rainfall and the maximum 3 days’accumulated rainfall at the 8 coastal stations induced by each category of TCs during the TC landfall period(a couple of days before and after TC landfalling time)from 1950 to 2013 are computed by the percentile estimation and illustrated by *** boxplots can be used to estimate the rainfall induced by landfalling TC of the same category in the *** statistical boxplot scheme is further coupled with the model outputs from the European Centre for Medium-Range Weather forecasts(ECMWF)to predict the rainfall induced by landfalling TCs along the coastal *** TCs landfalling in south China from 2014 to 2017 and the corresponding rainfall at the 8 stations area are used to evaluate the performance of these boxplots and coupled boxplots *** show that the statistical boxplots scheme and coupled boxplots scheme can perform better than ECMWF model in the operational rainfall forecast along the coastal area in south China.

关键词： tropical cyclone coastal area rainfall forecast statistical boxplot scheme coupled boxplot scheme

Improvement of displacement error of rainfall and wind field forecast associated with landfalling tropical cyclone AMPHAN

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Tropical Cyclone Research and Review 2022年第3期11卷 146-162页

作者： S.D.Kotal S.K.Bhattacharya India Meteorological Department Ministry of Earth Science Government of IndiaNew DelhiIndia

Spatial distribution of rainfall and wind speed forecast errors associated with landfalling tropical cyclones(TC)occur significantly due to incorrect location forecast by numerical *** major areas of errors are:(i)over-estimation over the model forecast locations and(ii)underestimation over the observed locations of the TCs.A modification method is proposed for real-time improvement of rainfall and wind field forecasts and demonstrated for the typical TC AMPHAN over the Bay of Bengal in *** proposed method to improve the model forecasts is a relocation method through shifting of model forecast locations of TC to the real-time official forecast locations of India Meteorological Department(IMD).The modification is applied to the forecasts obtained from the operational numerical model,the Global forecast System(GFS)of *** of the proposed method shows considerable improvement of both the parameters over both the *** rainfall forecast errors due to displacement are found to have improved by 44.1%–69.8%and 72.1%–85.2%over the GFS forecast locations and over the observed locations respectively for the respective forecast lead times 48 h,72 h,and 96 ***,the wind speed forecasts have improved by 27.6%–56.0%and 63.7%–84.6%over the GFS forecast locations and over the observed locations respectively for the respective forecast lead times 60 h,72 h,and 84 *** results show that the proposed technique has capacity to provide improved spatial distributions of rainfall and wind speed forecasts associated with landfalling TCs and useful guidance to operational forecasters.

关键词： Tropical cyclone Track forecast rainfall forecast Wind field Spatial distribution North Indian ocean

Impact of assimilating Taiwan＇s coastal radar radial velocity on forecasting Typhoon Morakot (2009) in southeastern China using a WRF-based EnKF

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Science China Earth Sciences 2017年第2期60卷 315-327页

作者： YUE Jian MENG ZhiYong Laboratory for Climate and Ocean-Atmosphere Studies Department of Atmospheric and Oceanic Sciences School of Physics Peking University Beij'ing 100871 China

This study explores for the first time the impact of assimilating radial velocity(Vr)observations from a single or multiple Taiwan's coastal radars on tropical cyclone(TC)forecasting after landfall in the Chinese mainland by using a Weather Research and forecasting model(WRF)-based ensemble Kalman filter(EnKF)data assimilation *** Morakot(2009),which caused widespread damage in the southeastern coastal regions of the mainland after devastating Taiwan,was chosen as a case *** results showed that assimilating Taiwan's radar Vr data improved environmental field and steering flow and produced a more realistic TC position and structure in the final EnKF cycling ***,the subsequent TC track and rainfall forecasts in southeastern China were *** addition,better observations of the TC inner core by Taiwan's radar was a primary factor in improving TC rainfall forecast in the Chinese mainland.

关键词： Radial velocity EnKF TC track forecast rainfall forecast Chinese mainland

Numerical Research on Effects Upon Precipitation forecast of Doppler-Radar Estimated Precipitation and Retrieved Wind Field Under Different Model Initial Schemes

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Acta meteorologica Sinica 2007年第1期21卷 98-113页

作者：王叶红赵玉春崔春光 Wuhan Institute of Heavy Rain CMA Wuhan Central Meteorological Observatory

On the basis of the joint estimated 1-h precipitation from Changde, Jingzhou, and Yichang Doppler radars as well as Wuhan digital radar, and the retrieved wind fields from Yichang and Jingzhou Doppler radars, a series of numerical experiments with an advanced regional η-coordinate model （AREM） under different model initial schemes, i.e., Grapes-3DVAR, Barnes objective analysis, and Barnes-3DVAR, are carried out for a torrential rain process occurring along the Yangtze River in the 24-h period from 2000 BT 22 July 2002 to investigate the effects of the Doppler-radar estimated rainfall and retrieved winds on the rainfall forecast. The main results are as follows：（1） The simulations are obviously different under three initial schemes with the same data source （the radiosounding and T213L31 analysis）. On the whole, Barnes-3DVAR, which combines the advantages of the Barnes objective analysis and the Grapes-3DVAR method, gives the best simulations： well-simulated rain band and clear mesoscale structures, as well as their location and intensity close to observations. （2） Both Barnes-3DVAR and Grapes-3DVAR schemes are able to assimilate the Doppler-radar estimated rainfall and retrieved winds, but differences in simulation results are very large, with Barnes-3DVAR＇s simulation much better than Grapes-3DVAR＇s. （3） Under Grapes- 3DVAR scheme, the simulation of 24-h rainfall is improved obviously when assimilating the Doppler-radar estimated precipitation into the model in compared with the control experiment; but it becomes a little worse when assimilating the Doppler-radar retrieved winds into the model, and it becomes worse obviously when assimilating the Doppler-radar estimated precipitation as well as retrieved winds into the model. However, the simulation is different under Barnes-3DVAR scheme. The simulation is improved to a certain degree no matter assimilating the estimated precipitation or retrieved winds, or both of them. The result is the best when assimilating bo

关键词： Doppler-radar estimated precipitation retrieved winds assimilation rainfall forecast

An Assessment of the Seasonal rainfall and Its Societal Implications in Zanzibar Islands during the Season of October to December, 2019

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Atmospheric and Climate Sciences 2020年第4期10卷 509-529页

作者： K. H. Kai A. L. Kijazi S. E. Osima Tanzania Meteorological Authority (TMA) Kisauni Zanzibar Tanzania TMA Ubungo Plaza Dar es Salaam Tanzania

The assessment of the performance of the October to December (OND), 2019 rainfall season in Zanzibar (Unguja and Pemba) with reference to local downscaled Tanzania Meteorological Authority (TMA) forecast, and regional (Intergovernmental Authority on Development Climate Prediction and Application Center (IGAD-ICPAC) weather forecasts were assessed by comparing the long term average of OND rainfall data and previous OND rainfall seasons of 2016, 2017 and 2018 as well as extreme positive Indian Ocean Dipole (IOD) during OND seasons of 1961, 1994, 1997, 2006 and 2019 for Zanzibar. The study assessed zonal (u) and meridional (v) winds at 850 and 200 mb, monthly and dekadal sea surface temperature (SST);the Madden Julien Oscillations (MJO) forecast reports and the ocean heat content data. Both gridded and observed datasets were processed into dekadal, monthly and seasonal averages and then analysed. The results revealed that, based on the observations, above normal rainfall of 936 and 908 mm were reported at stations of Kisauni (Unguja) and Karume airport (Pemba) during 2019 OND season. This amount was the first and second ever recorded for the extreme positive IOD during OND seasons of 1961, 1994, 1997, 2006 and 2019, and also the first for the previous higher OND rainfall seasons of 2016, 2017 and 2018 which was highly variable. Moreover, these values were second ever-recorded highest OND rainfall since 1916 to 2019 where the first one was observed in 1961. Furthermore, the results revealed that 2019 OND seasonal rainfall had the highest amount of contribution based on historical climatology. For instance, the 2019 OND rainfall for Kisauni, Pemba airport and Matangatuani contributed to 198%, 303% and 231% of the long term (1987-2016) mean OND rainfall in Zanzibar. Indeed, the results show that the presence of the MJO during OND and the enhanced positive IOD was among the causes for the observed wetness of the 2019 OND in Zanzibar and most parts of the country. Moreover,

关键词： OND rainfall forecast Performance Sea Surface Temperatures MJO and IOD

Application of Wavelet Random Coupling Model in Monthly rainfall Prediction

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Journal of Northeast Agricultural University(English Edition) 2011年第4期18卷 65-69页

作者： DONG Lili XU Shuqin LIU Yang WANG Yunhe College of Water Conservancy and Architecture Northeast Agricultural University Harbin 150030 China

A Trous algorithm of wavelet transform was used to decompose wavelet signal, and the cross-correlation analysis was used to analyze the sequence of each wavelet transform, and then the mathematical model correspond with wavelet transform sequence was established, finally wavelet random coupling model was obtained by wavelet reconstruction algorithm. Then, according to the rainfall data in crop growth period of Farm Chahayang from 1956 to 2008, the wavelet random coupling model was established to fit the model prediction test. The results showed that the prediction and fitting accuracy of the model was high, the model could reflect the rainfall variation regulation in the region, and it was a practical prediction model. It was very important for us to determine reasonably irrigation schedule and to use efficiency coefficient of precipitation resource.

关键词： wavelet random coupling model Farm Chahayang rainfall forecast Trous algorithm