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.

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 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 Extent of diurnal cycle of rainfall and its intra seasonal variation over coastal Tamil Nadu during north east monsoon season

MAUSAM ◽  
2022 ◽  
Vol 73 (1) ◽  
pp. 1-18
Author(s):  
Y.E.A. RAJ ◽  
B. AMUDHA
Keyword(s):  
Diurnal Variation ◽  
Diurnal Cycle ◽  
Tamil Nadu ◽  
Monsoon Season ◽  
Statistical Significance ◽  
Early Morning ◽  
Rainfall Anomaly ◽  
Land Breeze ◽  
North East ◽  
Hourly Rainfall

The diurnal variation of north east monsoon rainfall of coastal Tamil Nadu represented by four coastal stations Chennai Nungambakkam (Nbk), Chennai Meenambakkam (Mbk), Nagapattinam (Npt) and Pamban (Pbn)  was  studied in detail based on hourly rainfall data of rainy days only, for the period 1 Oct-31 Dec for the 47/48  year period 1969-2016/2017.  Mean Octet rainfall and its anomaly were computed for the 8 octets  00-03,…., 21-24 hrs of the day and the anomaly was tested for statistical significance. Various analysis for the individual months of Oct, Nov, Dec and the entire period Oct-Dec were separately conducted.  The basic technique of evolutionary histogram analysis supplemented by harmonic analysis of octet mean rainfall anomaly was used to detect the diurnal cycle signal. Two indices  named as  diurnal variation of  rainfall index and coefficient of mean absolute octet rainfall anomaly representing the intensity of diurnal variation  in dimensionless numbers were defined,  computed  and interpreted. The analysis based on the above techniques revealed that the diurnal signal which shows an early morning maximum and late afternoon minimum of octet rainfall is well defined in Oct, decreases in Nov and further decreases in Dec for all the 4 stations. Though the diurnal variation manifests a well defined pattern in Dec the signal is not statistically significant in most cases. For Nbk and Mbk there is a weak secondary peak of octet rainfall anomaly occurring in the forenoon and afternoon respectively in Oct and Dec suggesting the presence of semi-diurnal variation of rainfall. Stationwise, the diurnal signal is most well defined for each month/season in Pbn followed by Npt, Nbk and then Mbk.   The physical causes behind the diurnal signal and its decrease as the north east monsoon season advances from Oct to Dec have been deliberated. The well known feature of nocturnal maximum of oceanic convection influencing a coastal station with maritime climate and the higher saturation at the lower levels of the upper atmosphere in the early morning hours have been advanced as some of the causes. For the much more complex feature of decrease of diurnal signal with the  advancement of the season, the decrease of minimum surface temperature over coastal Tamil Nadu from Oct to Dec causing an early morning conceptual land breeze has been shown as one of the plausible causes  based on analysis of temperature and wind.  Scope for further work based on data from automatic weather stations, weather satellites and Doppler Weather Radars has been discussed.

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.

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 Diurnal variation of leukocyte counts affects the indirect estimation of reference intervals

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Antje Torge ◽  
Rainer Haeckel ◽  
Mustafa Özcürümez ◽  
Alexander Krebs ◽  
Ralf Junker
Keyword(s):  
Diurnal Variation ◽  
Indirect Method ◽  
Venous Blood ◽  
Direct Methods ◽  
Reference Intervals ◽  
Indirect Methods ◽  
Indirect Estimation ◽  
Late Afternoon ◽  
Reference Limits ◽  
Leukocyte Counts

Abstract It has been observed that the estimation of reference intervals of leukocytes in whole venous blood leads to higher upper reference limits (uRLs) with indirect methods than has been reported in the literature determined by direct approaches. This phenomenon was reinvestigated with a newer, more advanced indirect method, and could be confirmed. Furthermore, a diurnal variation was observed with lower values during the morning and higher values in the late afternoon and at night. This observation can explain why indirect approaches using samples collected during 24 h lead to higher uRLs than direct methods applied on samples collected presumably in the morning.

scholarly journals Meals for two: foraging activity of the butterflyfish Chaetodon Striatus (perciformes) in southeast Brazil

2005 ◽  
Vol 65 (2) ◽  
pp. 211-215 ◽  
Author(s):  
R. M. Bonaldo ◽  
J. P. Krajewski ◽  
I. Sazima
Keyword(s):  
Benthic Invertebrates ◽  
Early Morning ◽  
Southeastern Brazil ◽  
Foraging Activity ◽  
Feeding Rates ◽  
Western Atlantic ◽  
Late Afternoon ◽  
Sea Floor ◽  
Rocky Reefs ◽  
Feeding Activities

The banded butterflyfish (Chaetodon striatus) from the tropical and subtropical western Atlantic is a territorial, diurnal forager on benthic invertebrates. It is usually seen moving singly or in pairs, a few meters above the sea floor. We studied the foraging activity of C. striatus on rocky reefs in southeastern Brazil. This fish spent about 11 h and 30 min per day on feeding activities, and preferred colonies of non-scleratinian anthozoans over sandy and rocky substrata while foraging. The lowest feeding rates were recorded in the early morning and late afternoon, but we found no further differences between feeding rates throughout the day. We also found no differences between the feeding rates of paired and single individuals.

scholarly journals Thermal ecology and activity patterns of the lizard community of the Restinga of Jurubatiba, Macaé, RJ

2001 ◽  
Vol 61 (2) ◽  
pp. 287-294 ◽  
Author(s):  
F. H. HATANO ◽  
D. VRCIBRADIC ◽  
C. A. B. GALDINO ◽  
M. CUNHA-BARROS ◽  
C. F. D. ROCHA ◽  
...  
Keyword(s):  
Body Temperature ◽  
Rio De Janeiro ◽  
Activity Patterns ◽  
Early Morning ◽  
Thermal Ecology ◽  
Congeneric Species ◽  
Late Afternoon ◽  
Hemidactylus Mabouia ◽  
Environmental Temperatures

We analyzed the thermal ecology and activity patterns of the lizard community from the Restinga of Jurubatiba, Rio de Janeiro, Brazil. The broadest activity was that of Tropidurus torquatus, a sit-and-wait forager, while the active foraging teiid Cnemidophorus littoralis had the shortest activity. The nocturnal gekkonid Hemidactylus mabouia was found active during the day only during early morning and late afternoon, when environmental temperatures are low. Body temperature was highest for Cnemidophorus littoralis and lowest for the two Mabuya species. The patterns found here are discussed and compared to those of congeneric species in other habitats in Brazil.

scholarly journals Observed and predicted characteristics of equatorial F1 layer during solar minimum

2014 ◽  
Vol 32 (5) ◽  
pp. 571-580 ◽  
Author(s):  
C.-C. Lee
Keyword(s):  
Seasonal Variation ◽  
Diurnal Variation ◽  
Solar Minimum ◽  
Shape Parameter ◽  
Early Morning ◽  
Peak Height ◽  
Time Range ◽  
Occurrence Probability ◽  
Peak Density

Abstract. This study aims to assess the predictability of IRI-2012 on the equatorial F1 layer during solar minimum. The observed characteristics of F1 layer by the Jicamarca digisonde are compared with the model outputs. The results show that the time range for F1-layer appearance of observation is longer than that of IRI-2012, by at least 1 h in the early morning and later afternoon. In IRI-2012, there are three options for the occurrence probability of F1 layer: IRI-95, Scotto-97 no L, and Scotto-97 with L options. The first option predicts the probability well, but the last two underestimate the probability. The peak density of F1 layer (NmF1) of observation is very close to that of IRI-2012. For the F1 peak height (hmF1), the modeled values are smaller than the observed ones. The observed seasonal variation of hmF1 is not found in the modeled results. Nevertheless, the observed diurnal variation of hmF1 is similar to the modeled results with the B0 choices of Bil-2000 and ABT-2009. Regarding the shape parameter, the values of D1 (the shape parameter of F1 layer in observation) are much greater than the values of C1 (the shape parameter of F1 layer in IRI-2012). The D1 values are 3–6 times the C1 values. The diurnal variation of D1 is similar to that of C1, but the seasonal variation of D1 is not.

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