Variation Characteristics of Sunshine Time in Changjiang River Valley in Recent 50 Years

2011 ◽  
Vol 71-78 ◽  
pp. 3137-3141 ◽  
Author(s):  
Shi Gang Han
Keyword(s):  
Sichuan Basin ◽  
Sunshine Duration ◽  
River Valley ◽  
Seasonal Difference ◽  
Tibet Plateau ◽  
Changjiang River ◽  
Time Data ◽  
The Changjiang River ◽  
Variation Characteristics ◽  
Qinghai Tibet Plateau

By using the sunshine time data from 260 meteorological observation stations in Changjiang river valley from 1960 to 2009, the features of sunshine time in this area are studied. The results show that the highest sunshine time place is Qinghai-Tibet Plateau which is located in the source of the Changjiang river, and the sunshine time is about 2200-3000 h.a-1. The lowest sunshine time place is Sichuan Basin , and the sunshine time is about 1000-1600 h.a-1. The place of middle sunshine time is the midstream and down stream of Changjiang river, and the sunshine time is about 2000 h.a-1. There is a trend of decreasing with the sunshine time in zone 1, and the value is 54.2 h.10a-1. The decreasing value of zone 2 is 38.3h.10a-1. There is a trend of “rise first, down after” with sunshine time in zone 3. There is obvious seasonal difference in sunshine duration，with bigger decreasing amplitude in summer and winter than that in autumn. The variation trend of sunshine time is not obvious in spring.

Eunotia (Bacillariophyta) biodiversity from high altitude, freshwater habitats in the Mugecuo Scenic Area, Sichuan Province, China

Phytotaxa ◽  
2019 ◽  
Vol 394 (2) ◽  
pp. 133 ◽  
Author(s):  
FEN LUO ◽  
QINGMIN YOU ◽  
PAN YU ◽  
WANTING PANG ◽  
QUANXI WANG
Keyword(s):  
New Species ◽  
Sichuan Basin ◽  
Tibet Plateau ◽  
Hengduan Mountains ◽  
New Taxon ◽  
Monsoon Climate ◽  
Two New Species ◽  
Freshwater Habitats ◽  
The Sichuan Basin ◽  
Qinghai Tibet Plateau

Mugecuo Scenic Area is located in the northern Hengduan Mountains between the Sichuan Basin and the Qinghai-Tibet Plateau and has a subtropical humid monsoon climate. The area is at an altitude of 2600–3800 m above sea level (asl), with water originating mostly from melting mountain snow. In the region, a total of 20 Eunotia species have been identified, including two new species: E. mugecuo sp. nov., consisting of valves arched, clavate, ends broadly rounded, and terminal raphe fissures at the junction between valve face and mantle. The other newly-identified species is classified named as E. filiformis sp. nov., consisting of valves gently bent, ends not noticeably or only slightly inflated, broadly rounded, with external terminal raphe fissures curving in an angle of 180° back from apical nodules. Five newly recorded species have been identified in China, including E. odebrechtiana, E. michaelis, E. pomeranica, E. pseudogroenlandica and E. superpaludosa. Here, we discuss the new species and new taxon records through light and scanning microscopic documentation of valve morphology, along with key internal and external valve characteristics, and analyze the distribution of Eunotia in the Mugecuo Scenic Area.

scholarly journals Variation Characteristics of Summer Water Vapor Budget and Its Relationship with the Precipitation over the Sichuan Basin

Water ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 2533
Author(s):  
Dongmei Qi ◽  
Yueqing Li ◽  
Changyan Zhou
Keyword(s):  
Water Vapor ◽  
Sichuan Basin ◽  
Summer Precipitation ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Tibet Plateau ◽  
Daily Precipitation Data ◽  
Variation Characteristics ◽  
The Sichuan Basin ◽  
Water Vapor Budget

Based on the daily precipitation data from the meteorological stations in Sichuan and the monthly average ERA-Interim reanalysis data from 1979 to 2016, the variation characteristics of summer water vapor budget in the Sichuan Basin and its relationship with precipitation are discussed in this study. The results show that, in summer, the water vapor in the Sichuan Basin and its four sub-basins flows in from the southern and western boundaries and flows out through the eastern and northern boundaries, and the basin is obviously a water vapor sink. From 1979 to 2016, the water vapor inflow from the southern and western boundaries significantly decreased, as well as the water vapor outflow through the eastern boundary. The summer precipitation in the Sichuan Basin is significantly positively correlated with the water vapor inflow at the southern boundary and net water vapor budget of the basin in the same period, and it is negatively correlated with the water vapor outflow at the northern boundary. The southern and northern boundaries are the two most important boundaries for the summer precipitation in the Sichuan Basin. Additionally, this study reveals that, under the multi-scale topography on the east side of the Tibet Plateau, the spatio-temporal distribution of precipitation in the Sichuan Basin results from the interactions between the unique topography of the Sichuan Basin and the different modes of water-vapor transport from low latitudes. The atmospheric circulation over the key area of air–sea interaction in the tropical region and its accompanying systems, as well as the anomalies of regional circulations and water vapor transport over the eastern China and Sichuan Basin, are the main reasons for the variation in summer precipitation in the Sichuan Basin.

scholarly journals Precipitation and Minimum Temperature are Primary Climatic Controls of Alpine Grassland Autumn Phenology on the Qinghai-Tibet Plateau

2020 ◽  
Vol 12 (3) ◽  
pp. 431 ◽  
Author(s):  
Shuai An ◽  
Xiaoqiu Chen ◽  
Xiaoyang Zhang ◽  
Weiguang Lang ◽  
Shilong Ren ◽  
...  
Keyword(s):  
Minimum Temperature ◽  
Climatic Factors ◽  
Sunshine Duration ◽  
Controlling Factor ◽  
Alpine Grassland ◽  
Tibet Plateau ◽  
Linear Regression Models ◽  
Alpine Grasslands ◽  
Optimum Length ◽  
Qinghai Tibet Plateau

Autumn phenology is a crucial indicator for identifying the alpine grassland growing season’s end date on the Qinghai-Tibet Plateau (QTP), which intensely controls biogeochemical cycles in this ecosystem. Although autumn phenology is thought to be mainly influenced by the preseason temperature, precipitation, and insolation in alpine grasslands, the relative contributions of these climatic factors on the QTP remain uncertain. To quantify the impacts of climatic factors on autumn phenology, we built stepwise linear regression models for 91 meteorological stations on the QTP using in situ herb brown-off dates, remotely sensed autumn phenological metrics, and a multi-factor climate dataset during an optimum length period. The results show that autumn precipitation has the most extensive influence on interannual variation in alpine grassland autumn phenology. On average, a 10 mm increase in autumn precipitation during the optimum length period may lead to a delay of 0.2 to 4 days in the middle senescence date (P < 0.05) across the alpine grasslands. The daily minimum air temperature is the second most important controlling factor, namely, a 1 °C increase in the mean autumn minimum temperature during the optimum length period may induce a delay of 1.6 to 9.3 days in the middle senescence date (P < 0.05) across the alpine grasslands. Sunshine duration is the third extensive controlling factor. However, its influence is spatially limited. Moreover, the relative humidity and wind speed also have strong influences at a few stations. Further analysis indicates that the autumn phenology at stations with less autumn precipitation is more sensitive to precipitation variation than at stations with more autumn precipitation. This implies that autumn drought in arid regions would intensely accelerate the leaf senescence of alpine grasslands. This study suggests that precipitation should be considered for improving process-based autumn phenology models in QTP alpine grasslands.

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