scholarly journals Changes in Duration-Related Characteristics of Late-Summer Precipitation over Eastern China in the Past 40 Years

2011 ◽  
Vol 24 (21) ◽  
pp. 5683-5690 ◽  
Author(s):  
Jian Li ◽  
Rucong Yu ◽  
Weihua Yuan ◽  
Haoming Chen
Keyword(s):  
Short Duration ◽  
North China ◽  
Eastern China ◽  
Summer Precipitation ◽  
Late Summer ◽  
Early Morning ◽  
Rainfall Amount ◽  
Rainfall Events ◽  
Late Afternoon ◽  
Long Duration

Abstract Duration is a key feature of rainfall events that is closely related to rainfall mechanisms and influences. This study analyzes the decadal change in the duration-related characteristics of late-summer (July–August) precipitation over eastern China during 1966–2005. Accompanying the southern-flooding and northern-drought (SFND) pattern of rainfall amount over the eastern China in recent decades, the duration-related rainfall structure also experienced significant changes. In North China, the frequency of short duration rainfall events decreased and their intensity increased. The decadal decreases of rainfall amount over North China are largely contributed by long duration rainfall events, especially those occurring between midnight and morning. In the mid-to-lower reaches of the Yangtze River valley, both the frequency and amount of long duration precipitation have significantly increased. The mean and maximum duration time of late-summer precipitation has increased 0.85 and 7.61 h, respectively. Considerable increases of rainfall amount of two kinds of precipitation, the short and medium duration rainfall events in the late afternoon and the long duration rainfall events in the early morning, contribute to the “southern-flooding.” Despite the differences between the northern and southern region, there is a common feature of their decadal precipitation changes that the intensity of short duration rainfall in the late afternoon has shown an increasing trend.

scholarly journals Seasonal Variation of the Diurnal Cycle of Rainfall in Southern Contiguous China

2008 ◽  
Vol 21 (22) ◽  
pp. 6036-6043 ◽  
Author(s):  
Jian Li ◽  
Rucong Yu ◽  
Tianjun Zhou
Keyword(s):  
Seasonal Variation ◽  
Diurnal Cycle ◽  
Radiative Forcing ◽  
Early Morning ◽  
Rain Gauge ◽  
Rainfall Events ◽  
Late Afternoon ◽  
Long Duration ◽  
China Region ◽  
Afternoon Peak

Abstract Hourly station rain gauge data are employed to study the seasonal variation of the diurnal cycle of rainfall in southern contiguous China. The results show a robust seasonal variation of the rainfall diurnal cycle, which is dependent both on region and duration. Difference in the diurnal cycle of rainfall is found in the following two neighboring regions: southwestern China (region A) and southeastern contiguous China (region B). The diurnal cycle of annual mean precipitation in region A tends to reach the maximum in either midnight or early morning, while precipitation in region B has a late-afternoon peak. In contrast with the weak seasonal variation of the diurnal phases of precipitation in region A, the rainfall peak in region B shifts sharply from late afternoon in warm seasons to early morning in cold seasons. Rainfall events in south China are classified into short- (1–3 h) and long-duration (more than 6 h) events. Short-duration precipitation in both regions reaches the maximum in late afternoon in warm seasons and peaks in either midnight or early morning in cold seasons, but the late-afternoon peak in region B exists during February–October, while that in region A only exists during May–September. More distinct differences between regions A and B are found in the long-duration rainfall events. The long-duration events in region A show dominant midnight or early morning peaks in all seasons. But in region B, the late-afternoon peak exists during July–September. Possible reasons for the difference in the diurnal cycle of rainfall between the two regions are discussed. The different cloud radiative forcing over regions A and B might contribute to this difference.

scholarly journals Diurnal Variation of Summer Precipitation across the Central Tian Shan Mountains

2017 ◽  
Vol 56 (6) ◽  
pp. 1537-1550 ◽  
Author(s):  
Jian Li ◽  
Tianru Chen ◽  
Nina Li
Keyword(s):  
Diurnal Variation ◽  
Summer Precipitation ◽  
Early Morning ◽  
Rainfall Events ◽  
Late Afternoon ◽  
Southern Basin ◽  
Hourly Rainfall ◽  
Tian Shan Mountains ◽  
Afternoon Peak ◽  
Tian Shan

AbstractThe climatic features of the diurnally varying summer precipitation over and around the central Tian Shan Mountains are investigated. Both the hourly rainfall data observed at eight stations along a transect across the mountains and the convective index derived from the satellite data show that there are three distinct regimes: the early morning peak at stations to the south of the mountains, the late afternoon peak at stations on the mountains, and the night peak at stations to the north of the mountains. The relation between regimes of diurnal variation is analyzed. By defining the regional rainfall event (RRE), the initial stations of each RRE are recorded. The early morning rainfall in the southern periphery of the mountains is triggered locally in the southern basin. Both the late afternoon peak over the mountains and the night peak in the northern periphery are influenced by mountain-originated rainfall events. These rainfall events appear over the mountains in the afternoon, and some of them move northward and lead to the nocturnal rainfall in the northern basin. The triggering of convection in the afternoon over the mountains and that in the early morning in the southern basin is related to the diurnally varying wind and thermodynamic conditions over and around the mountains. Low-level convergence with thermodynamic instability appears at noon (night) over the mountains (in the southern basin) just before the start of the convection.

Fine-scale characteristics of summer precipitation over Cang Mountain

2021 ◽  
Author(s):  
Mengke Zhang ◽  
Jian Li ◽  
Nina Li
Keyword(s):  
Short Duration ◽  
Rainfall Intensity ◽  
Summer Precipitation ◽  
Early Morning ◽  
Rain Gauge ◽  
Small Scale ◽  
Fine Scale ◽  
Maximum Rainfall ◽  
Long Duration ◽  
Scale Characteristics

AbstractFine-scale characteristics of summer precipitation over Cang Mountain, a long and narrow mountain with a quasi-north-south orientation in Southwest China, are studied based on station and radar data. Three kinds of rainfall processes are classified according to the initial stations of regional rainfall events (RREs) by utilizing minute-scale rain gauge data. RREs initiating in the western part of Cang Mountain exhibit eastward evolution and tend to reach their maximum rainfall intensity on the mountaintop. The results indicate differences in the precipitation evolution characteristics between short-duration (1–3 h) and long-duration (at least 6 h) events. Short-duration events begin farther from the mountaintop and then propagate eastward, while long-duration events remain longer around the mountaintop. RREs that initiate from the eastern part of Cang Mountain display westward propagation and frequently reach their maximum rainfall intensity over the eastern slope of the mountain. Among them, short-duration events tend to propagate farther west of Cang Mountain at high speeds, but the westward evolution of long-duration events is mainly confined to the eastern part of Cang Mountain. For mountaintop-originated RREs, precipitation quickly reaches its maximum intensity after it starts and then continues for a long time around the mountaintop during the period from late afternoon to early morning. These findings provide references for the fine-scale prediction of precipitation evolution in small-scale mountainous areas.

Subseasonal Characteristics of Diurnal Variation in Summer Monsoon Rainfall over Central Eastern China

2010 ◽  
Vol 23 (24) ◽  
pp. 6684-6695 ◽  
Author(s):  
Weihua Yuan ◽  
Rucong Yu ◽  
Haoming Chen ◽  
Jian Li ◽  
Minghua Zhang
Keyword(s):  
Diurnal Variation ◽  
Summer Monsoon ◽  
Monsoon Rainfall ◽  
Eastern China ◽  
Early Morning ◽  
Summer Monsoon Rainfall ◽  
Rain Belt ◽  
Rainfall Events ◽  
Long Duration ◽  
Central Eastern

Abstract Subseasonal characteristics of the diurnal variation of the summer monsoon rainfall over central eastern China (25°–40°N, 110°–120°E) are analyzed using hourly station rain gauge data. Results show that the rainfall in the monsoon rain belt is dominated by the long-duration rainfall events (≥7 h) with early-morning peaks. The long-duration rainfall events and early-morning diurnal peaks experience subseasonal movement that is similar to that of the monsoon rain belt. When the monsoon rainfall is separated into the active and break periods, the long-duration early-morning precipitation dominates the active period, which is in sharp contrast to the short-duration (≤6 h) rainfall with leading late-afternoon diurnal peaks during the break period. The combination of different diurnal features of monsoon rainfall in the active and break monsoon periods also explains the less coherent diurnal phases of summer mean rainfall over central eastern China. The cause of the early-morning peak of rainfall during the active monsoon period is discussed.

scholarly journals Roles of anthropogenic forcings in the observed trend of decreasing late-summer precipitation over the East Asian transitional climate zone

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wei Zhao ◽  
Wen Chen ◽  
Shangfeng Chen ◽  
Hainan Gong ◽  
Tianjiao Ma
Keyword(s):  
Asian Summer Monsoon ◽  
Dominant Role ◽  
East Asian ◽  
Eastern China ◽  
Summer Precipitation ◽  
Late Summer ◽  
Water Vapor Transport ◽  
Anthropogenic Aerosol ◽  
Climate Zone ◽  
Drying Trend

AbstractObservations indicate that late-summer precipitation over the East Asian transitional climate zone (TCZ) showed a pronounced decreasing trend during 1951–2005. This study examines the relative contributions of anthropogenic [including anthropogenic aerosol (AA) and greenhouse gas (GHG)] and natural forcings to the drying trend of the East Asian TCZ based on simulations from CMIP5. The results indicate that AA forcing plays a dominant role in contributing to the drying trend of the TCZ. AA forcing weakens the East Asian summer monsoon via reducing the land-sea thermal contrast, which induces strong low-level northerly anomalies over eastern China, suppresses water vapor transport from southern oceans and results in drier conditions over the TCZ. In contrast, GHG forcing leads to a wetting trend in the TCZ by inducing southerly wind anomalies, thereby offsetting the effect of the AA forcing. Natural forcing has a weak impact on the drying trend of the TCZ due to the weak response of atmospheric anomalies.

scholarly journals Changes in Characteristics of Late-Summer Precipitation over Eastern China in the Past 40 Years Revealed by Hourly Precipitation Data

2010 ◽  
Vol 23 (12) ◽  
pp. 3390-3396 ◽  
Author(s):  
Rucong Yu ◽  
Jian Li ◽  
Weihua Yuan ◽  
Haoming Chen
Keyword(s):  
Yangtze River ◽  
Rainfall Intensity ◽  
Eastern China ◽  
Late Summer ◽  
Rain Gauge ◽  
Rainfall Amount ◽  
Yangtze River Valley ◽  
River Valley ◽  
The Yangtze River ◽  
Hourly Rainfall

Abstract Using hourly station rain gauge data during 1966–2005, the authors studied changes in the characteristics of the late-summer (July–August) rainfall, which has exhibited a so-called southern flooding and northern drought (SFND) pattern over eastern China in recent decades. Although the rainfall amount and frequency have significantly increased (decreased) in the mid–lower reaches of the Yangtze River valley (North China) during this period, the rainfall intensity has decreased (increased). This finding differs from previous results based on daily data, which showed that the rainfall intensity has increased in the mid–lower reaches of the Yangtze River valley. In this region, the mean rainfall hours on rainy days have increased because of the prolonged rainfall duration, which has led to an increased daily rainfall amount and to a decreased hourly rainfall intensity. Results also show that the SFND pattern is mostly attributed to changes in precipitation with moderate and low intensity (≤10 mm h−1), which contributes 65% (96%) of rainfall amount to the “flooding” (“drought”) in the mid–lower reaches of the Yangtze River valley. Neither frequency nor amount of strong intensity (>20 mm h−1) rainfall exhibits the SFND pattern.

Regimes of Diurnal Variation of Summer Rainfall over Subtropical East Asia

2012 ◽  
Vol 25 (9) ◽  
pp. 3307-3320 ◽  
Author(s):  
Weihua Yuan ◽  
Rucong Yu ◽  
Minghua Zhang ◽  
Wuyin Lin ◽  
Haoming Chen ◽  
...  
Keyword(s):  
Diurnal Variation ◽  
East Asia ◽  
Hydrological Cycle ◽  
Eastern China ◽  
Summer Rainfall ◽  
Early Morning ◽  
Rain Gauge ◽  
Western China ◽  
The Tibetan Plateau ◽  
Late Afternoon

Using hourly rain gauge records and Tropical Rainfall Measuring Mission 3B42 from 1998 to 2006, the authors present an analysis of the diurnal characteristics of summer rainfall over subtropical East Asia. The study shows that there are four different regimes of distinct diurnal variation of rainfall in both the rain gauge and the satellite data. They are located over the Tibetan Plateau with late-afternoon and midnight peaks, in the western China plain with midnight to early-morning peaks, in the eastern China plain with double peaks in late afternoon and early morning, and over the East China Sea with an early-morning peak. No propagation of diurnal phases is found from the land to the ocean across the coastlines. The different diurnal regimes are highly correlated with the inhomogeneous underlying surface, such as the plateau, plain, and ocean, with physical mechanisms consistent with the large-scale “mountain–valley” and “land–sea” breezes and convective instability. These diurnal characteristics over subtropical East Asia can be used as diagnostic metrics to evaluate the physical parameterization and hydrological cycle of climate models over East Asia.

scholarly journals Summer Precipitation Frequency, Intensity, and Diurnal Cycle over China: A Comparison of Satellite Data with Rain Gauge Observations

2008 ◽  
Vol 21 (16) ◽  
pp. 3997-4010 ◽  
Author(s):  
Tianjun Zhou ◽  
Rucong Yu ◽  
Haoming Chen ◽  
Aiguo Dai ◽  
Yang Pan
Keyword(s):  
Eastern China ◽  
Precipitation Amount ◽  
Rain Gauge ◽  
Rainfall Amount ◽  
The Tibetan Plateau ◽  
Precipitation Frequency ◽  
Rain Gauge Data ◽  
Late Afternoon ◽  
Pattern Correlation ◽  
Gauge Data

Abstract Hourly or 3-hourly precipitation data from Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN) and Tropical Rainfall Measuring Mission (TRMM) 3B42 satellite products and rain gauge records are used to characterize East Asian summer monsoon rainfall, including spatial patterns in June–August (JJA) mean precipitation amount, frequency, and intensity, as well as the diurnal and semidiurnal cycles. The results show that the satellite products are comparable to rain gauge data in revealing the spatial patterns of JJA precipitation amount, frequency, and intensity, with pattern correlation coefficients for five subregions ranging from 0.66 to 0.94. The pattern correlation of rainfall amount is higher than that of frequency and intensity. Relative to PERSIANN, the TRMM product has a better resemblance with rain gauge observations in terms of both the pattern correlation and root-mean-square error. The satellite products overestimate rainfall frequency but underestimate its intensity. The diurnal (24 h) harmonic dominates subdaily variations of precipitation over most of eastern China. A late-afternoon maximum over southeastern and northeastern China and a near-midnight maximum over the eastern periphery of the Tibetan Plateau are seen in the rain gauge data. The diurnal phases of precipitation frequency and intensity are similar to those of rainfall amount in most regions, except for the middle Yangtze River valley. Both frequency and intensity contribute to the diurnal variation of rainfall amount over most of eastern China. The contribution of frequency to the diurnal cycle of rainfall amount is generally overestimated in both satellite products. Both satellite products capture well the nocturnal peak over the eastern periphery of the Tibetan Plateau and the late-afternoon peak in southern and northeastern China. Rain gauge data over the region between the Yangtze and Yellow Rivers show two peaks, with one in the early morning and the other later in the afternoon. The satellite products only capture the major late-afternoon peak.

Why Nocturnal Long-Duration Rainfall Presents an Eastward-Delayed Diurnal Phase of Rainfall down the Yangtze River Valley

2010 ◽  
Vol 23 (4) ◽  
pp. 905-917 ◽  
Author(s):  
Haoming Chen ◽  
Rucong Yu ◽  
Jian Li ◽  
Weihua Yuan ◽  
Tianjun Zhou
Keyword(s):  
Yangtze River ◽  
Large Scale ◽  
Southern China ◽  
Summer Rainfall ◽  
Early Morning ◽  
The Tibetan Plateau ◽  
The Yangtze River ◽  
Rainfall Events ◽  
Low Level ◽  
Long Duration

Abstract Hourly observational records and 6-hourly reanalysis data were used to investigate the influences of large-scale forcings on the diurnal variation of summer rainfall along the Yangtze River (YR). The results show that long-duration (more than six hours) rainfall events dominate the summer rainfall along the YR. These events tend to start during the night and to peak after several hours of development. The eastward-delayed initiation of the nocturnal long-duration rainfall events is thought to be due to the diurnal clockwise rotation of the low-tropospheric circulation, especially the accelerated nocturnal southwesterlies. In the early evening, the anomalous easterly flow toward the Tibetan Plateau (TP) causes low-level convergence over the Plateau’s eastern slope that induces the formation of rainfall in the upper YR valley. The anomalous wind sequentially rotates clockwise to a southerly flow at midnight and accelerates the meridional wind in the middle valley, resulting in the initiation of rainfall between 2300 and 0300 LST. In the early morning, the accelerated southwesterlies in southern China, when combined with decelerated winds in the north of the YR, causes a strong convergence along the YR and contributes to the early morning rainfall in the lower valley. Furthermore, the development of the convection systems is suppressed in the afternoon by the mid- and low-level warm advection downstream from the TP. This helps explain why long-duration events do not typically start in the afternoon in the upper YR valley.

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