scholarly journals Drought and Wetness Variability and the Respective Contribution of Temperature and Precipitation in the Qinghai-Tibetan Plateau

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Lele Zhang ◽  
Liming Gao
Keyword(s):  
Tibetan Plateau ◽  
Qaidam Basin ◽  
Linear Trend ◽  
Kendall Test ◽  
Precipitation Variability ◽  
Meteorological Forcing ◽  
Climatic Regions ◽  
Temperature And Precipitation ◽  
Respective Contribution ◽  
The Mean

Quantifying drought and wetness fluctuations is of great significance to the regional ecological environment and water resource security, especially in the fragile Qinghai-Tibetan Plateau (QTP). In this paper, the standardized precipitation evapotranspiration index (SPEI) was calculated based on the observed data and China Meteorological Forcing Dataset (CMFD) in the QTP for the period of 1979–2015, and the drought and wetness evolution based on the SPEI series and respective contribution of temperature and precipitation were also analyzed. Results indicated that meteorological stations are mainly concentrated in the eastern part of the plateau, which cannot reflect the drought and wetness trend of the whole QTP. The linear trend and Mann–Kendall test revealed that SPEI series calculated based on CMFD data at 1-, 3-, 6-, 9-, 12-, and 24-month time scales all showed significant upward trend p < 0.01 , indicating that the QTP as a whole tended to be wetter. Spatially, the regions with significant drying p < 0.1 and increased drought probability were mainly concentrated in the Qaidam Basin and the southern part of the QTP, and the mean contribution rates of temperature and precipitation variability to SPEI trend in these regions were 60% and −11%, respectively. The regions with significant wetting p < 0.1 and decreased drought probability were mainly concentrated in the northeast, central, and western parts of the plateau, and the mean contribution rates of temperature and precipitation variability to SPEI trend were −9% and 61% in these regions. From the statistics in different climatic regions, most of the arid and humid regions in the QTP tended to be drier, while the semiarid regions tended to be wetter.

scholarly journals An Early Miocene Lowland on the Northeastern Tibetan Plateau

2021 ◽  
Vol 9 ◽  
Author(s):  
Qian Tian ◽  
Xiaomin Fang ◽  
Yan Bai ◽  
Chihao Chen ◽  
Juzhi Hou ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Sea Level ◽  
Late Miocene ◽  
Qaidam Basin ◽  
Early Miocene ◽  
Annual Average ◽  
Northeastern Tibetan Plateau ◽  
The Mean ◽  
First Time ◽  
Glycerol Dialkyl Glycerol Tetraethers

The northeastern Tibetan Plateau (NE TP) has long been thought to be the last part of the Plateau to be raised, but this assumption has been challenged by recent analyses of fossil leaf energy, which have pointed to the possibility that the present surface altitude of ∼3,000 m above sea level (asl) in the Qaidam Basin (QB) was attained during the Oligocene. Here, for the first time, we present a record of glycerol dialkyl glycerol tetraethers (GDGTs) from a well-dated Cenozoic section in the QB. This record appears to demonstrate that the mean annual average paleotemperature of the QB was 28.4 ± 2.9°C at ∼18.0 Ma. This would suggest that the paleoelevation of the QB was only ∼1,488 m asl at that time and that a ∼1,500 m uplift was attained afterwards, in agreement with the massive shortening of the QB and the rapid drying of inland Asia since the late Miocene.

scholarly journals Long-term air temperature and precipitation variability in the Warta River catchment area

2015 ◽  
Vol 27 (1) ◽  
pp. 3-13 ◽  
Author(s):  
Piotr Ilnicki ◽  
Ryszard Farat ◽  
Krzysztof Górecki ◽  
Piotr Lewandowski
Keyword(s):  
River Basin ◽  
Air Temperature ◽  
Catchment Area ◽  
Precipitation Variability ◽  
Negative Influence ◽  
Mean Annual Precipitation ◽  
Temperature And Precipitation ◽  
Measurement Series ◽  
The Mean

Abstract The variability of the mean annual air temperature and precipitation totals in three periods: 1848–2010, 1951–2010 and 1981–2010 was investigated in the large Warta River basin, being the area with lowest rainfall in Poland. For the purposes of research, nine meteorological stations with the longest measurement series were selected. Air temperature increase in this river basin was similar than in neighbouring countries. In the last 30 years this trend kept increasing. The precipitation in the whole studied period was slightly increasing in the northern part of the Warta River basin, but decreasing in the southern part. The mean annual precipitation totals in the catchment area did not change visible. In the period 1981–2010, the precipitation totals show a small increase in the winter and spring and a decrease in summer. A negative influence of this climate change was not visible in the Warta River discharge. The main objectives of this study were the collection long-term records of air temperature and precipitation in the Warta River basin, and the statistical analysis of climate variability.

OSL chronology for lacustrine sediments recording high stands of Gahai Lake in Qaidam Basin, northeastern Qinghai–Tibetan Plateau

2010 ◽  
Vol 5 (2-3) ◽  
pp. 223-227 ◽  
Author(s):  
QiShun Fan ◽  
ZhongPing Lai ◽  
Hao Long ◽  
YongJuan Sun ◽  
XiangJun Liu
Keyword(s):  
Tibetan Plateau ◽  
Qaidam Basin ◽  
Lacustrine Sediments

scholarly journals Benchmarking homogenization algorithms for monthly data

2012 ◽  
Vol 8 (1) ◽  
pp. 89-115 ◽  
Author(s):  
V. K. C. Venema ◽  
O. Mestre ◽  
E. Aguilar ◽  
I. Auer ◽  
J. A. Guijarro ◽  
...  
Keyword(s):  
Time Series ◽  
Performance Metrics ◽  
Linear Trend ◽  
Simulated Data ◽  
Integrated Approach ◽  
Global Network ◽  
Temperature And Precipitation ◽  
Skill Scores ◽  
Simulated Network ◽  
The Individual

Abstract. The COST (European Cooperation in Science and Technology) Action ES0601: advances in homogenization methods of climate series: an integrated approach (HOME) has executed a blind intercomparison and validation study for monthly homogenization algorithms. Time series of monthly temperature and precipitation were evaluated because of their importance for climate studies and because they represent two important types of statistics (additive and multiplicative). The algorithms were validated against a realistic benchmark dataset. The benchmark contains real inhomogeneous data as well as simulated data with inserted inhomogeneities. Random independent break-type inhomogeneities with normally distributed breakpoint sizes were added to the simulated datasets. To approximate real world conditions, breaks were introduced that occur simultaneously in multiple station series within a simulated network of station data. The simulated time series also contained outliers, missing data periods and local station trends. Further, a stochastic nonlinear global (network-wide) trend was added. Participants provided 25 separate homogenized contributions as part of the blind study. After the deadline at which details of the imposed inhomogeneities were revealed, 22 additional solutions were submitted. These homogenized datasets were assessed by a number of performance metrics including (i) the centered root mean square error relative to the true homogeneous value at various averaging scales, (ii) the error in linear trend estimates and (iii) traditional contingency skill scores. The metrics were computed both using the individual station series as well as the network average regional series. The performance of the contributions depends significantly on the error metric considered. Contingency scores by themselves are not very informative. Although relative homogenization algorithms typically improve the homogeneity of temperature data, only the best ones improve precipitation data. Training the users on homogenization software was found to be very important. Moreover, state-of-the-art relative homogenization algorithms developed to work with an inhomogeneous reference are shown to perform best. The study showed that automatic algorithms can perform as well as manual ones.

Paleolake salinity evolution in the Qaidam Basin (NE Tibetan Plateau) between ~42 and 29 Ma: Links to global cooling and Paratethys sea incursions

2021 ◽  
Author(s):  
Chengcheng Ye ◽  
Yibo Yang ◽  
Xiaomin Fang ◽  
Weilin Zhang ◽  
Chunhui Song ◽  
...  
Keyword(s):  
Climate Change ◽  
Tibetan Plateau ◽  
Middle Eocene ◽  
Qaidam Basin ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Driving Mechanism ◽  
The Tibetan Plateau ◽  
Early Oligocene ◽  
Global Cooling

&lt;p&gt;Global cooling, the early uplift of the Tibetan Plateau, and the retreat of the Paratethys are three main factors that regulate long-term climate change in the Asian interior during the Cenozoic. However, the debated elevation history of the Tibetan Plateau and the overlapping climate effects of the Tibetan Plateau uplift and Paratethys retreat makes it difficult to assess the driving mechanism on regional climate change in a particular period. Some recent progress suggests that precisely dated Paratethys transgression/regression cycles appear to have fluctuated over broad regions with low relief in the northern Tibetan Plateau in the middle Eocene&amp;#8211;early Oligocene, when the global climate was characterized by generally continuous cooling followed by the rapid Eocene&amp;#8211;Oligocene climate transition (EOT). Therefore, a middle Eocene&amp;#8211;early Oligocene record from the Asian interior with unambiguous paleoclimatic implications offers an opportunity to distinguish between the climatic effects of the Paratethys retreat and those of global cooling.&lt;/p&gt;&lt;p&gt;Here, we present a complete paleolake salinity record from middle Eocene to early Miocene (~42-29 Ma) in the Qaidam Basin using detailed clay boron content and clay mineralogical investigations. Two independent paleosalimeters, equivalent boron and Couch&amp;#8217;s salinity, collectively present a three-staged salinity evolution, from an oligohaline&amp;#8211;mesohaline environment in the middle Eocene (42-~34 Ma) to a mesosaline environment in late Eocene-early Oligocene (~34-~29 Ma). This clay boron-derived salinity evolution is further supported by the published chloride-based and ostracod-based paleosalinity estimates in the Qaidam Basin. Our quantitative paleolake reconstruction between ~42 and 29 Ma in the Qaidam Basin resembles the hydroclimate change in the neighboring Xining Basin, of which both present good agreement with changes of marine benthic oxygen isotope compositions. We thus speculated that the secular trend of clay boron-derived paleolake salinity in ~42-29 Ma is primarily controlled by global cooling, which regulates regional climate change by influencing the evaporation capacity in the moisture source of Qaidam Basin. Superimposed on this trend, the Paratethys transgression/regression cycles served as an important factor regulating wet/dry fluctuations in the Asian interior between ~42 and ~34 Ma.&lt;/p&gt;

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