Extreme precipitation increases the productivity of a desert ephemeral plant community in Central Asia, but there is no slope position effect

Based on the output data from the Lagrangian flexible particle dispersion model (FLEXPART), we analyze the pathways of moisture to identify the moisture source areas for extreme precipitation in the summer half-year (April–September) over northern and southern Xinjiang, respectively. For both northern and southern Xinjiang, the local evaporation plays a decisive role for extreme precipitation in the summer half-year, of which contribution ratio accounts for 24.5% to northern Xinjiang and 30.2% to southern Xinjiang of all identified source areas. In addition, central Asia and northwestern Asia are the major moisture source areas as well and contribute similarly to extreme precipitation relative to local evaporation. For northern Xinjiang, central Asia surpasses northwestern Asia, and each of them contributes 24.1 and 18.8%, whereas northwestern Asia is somewhat more crucial than central Asia for southern Xinjiang, accounting 22.1 and 19.1%, respectively. Note that the three top-ranked moisture source areas make up a large proportion of total sources. Regarding the remaining source areas that also provide moisture, the contributions are entirely different for southern and northern Xinjiang. Originating from the North Atlantic Ocean, Europe, and the Mediterranean Sea, some water vapor enters northern Xinjiang and converge to precipitate, while this process is barely detectable for extreme precipitation over southern Xinjiang, which is affected by the westerly flow. On the contrary, the Arabian Sea, the Arabian Peninsula, and the Indian Peninsula contribute, even though slightly, to extreme precipitation over southern Xinjiang, which indicates that the meridional transport pathways from the Arabian Sea can carry moisture to this inland region.

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Ecosystem functional response across precipitation extremes in a sagebrush steppe

10.1101/195594 ◽

2017 ◽

Author(s):

Andrew T. Tredennick ◽

Andrew R. Kleinhesselink ◽

J. Bret Taylor ◽

Peter B. Adler

Keyword(s):

United States ◽

Soil Moisture ◽

Functional Response ◽

Community Composition ◽

Plant Community ◽

Extreme Precipitation ◽

Sagebrush Steppe ◽

Functional Responses ◽

The Relationship

ABSTRACTBackgroundPrecipitation is predicted to become more variable in the western United States, meaning years of above and below average precipitation will become more common. Periods of extreme precipitation are major drivers of interannual variability in ecosystem functioning in water limited communities, but how ecosystems respond to these extremes over the long-term may shift with precipitation means and variances. Long-term changes in ecosystem functional response could reflect compensatory changes in species composition or species reaching physiological thresholds at extreme precipitation levels.MethodsWe conducted a five year precipitation manipulation experiment in a sagebrush steppe ecosystem in Idaho, United States. We used drought and irrigation treatments (approximately 50% decrease/increase) to investigate whether ecosystem functional response remains consistent under sustained high or low precipitation. We recorded data on aboveground net primary productivity (ANPP), species abundance, and soil moisture. We fit a generalized linear mixed effects model to determine if the relationship between ANPP and soil moisture differed among treatments. We used nonmetric multidimensional scaling to quantify community composition over the five years.ResultsEcosystem functional response, defined as the relationship between soil moisture and ANPP, was similar among irrigation and control treatments, but the drought treatment had a greater slope than the control treatment. However, all estimates for the effect of soil moisture on ANPP overlapped zero, indicating the relationship is weak and uncertain regardless of treatment. There was also large spatial variation in ANPP within-years, which contributes to the uncertainty of the soil moisture effect. Plant community composition was remarkably stable over the course of the experiment and did not differ among treatments.DiscussionDespite some evidence that ecosystem functional response became more sensitive under sustained drought conditions, the response of ANPP to soil moisture was consistently weak and community composition was stable. The similarity of ecosystem functional responses across treatments was not related to compensatory shifts at the plant community level, but instead may reflect the insensitivity of the dominant species to soil moisture. These species may be successful precisely because they have evolved life history strategies which buffer them against precipitation variability.

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Application of Multiple Detection Data in the Analysis of Snowstorm Processes in Xinjiang during the Central Asia Extreme Precipitation Observation Test (CAEPOT)

Advances in Meteorology ◽

10.1155/2020/8845667 ◽

2020 ◽

Vol 2020 ◽

pp. 1-13

Author(s):

Yong Zeng ◽

Lianmei Yang ◽

Zepeng Tong ◽

Zuyi Zhang

Keyword(s):

Central Asia ◽

Millimeter Wave ◽

Extreme Precipitation ◽

Wind Field ◽

Particle Concentration ◽

Northwestern China ◽

Horizontal Wind ◽

Arid Areas ◽

Cloud Radar ◽

Physical Quantities

At present, there is insufficient research on the refinement of the vertical structure of winter snowstorm systems in arid areas, and, compared with the central and eastern China, the observation sites in arid areas of northwestern China are scarce. To deepen the understanding of dynamics and microphysical processes and improve the level of forecasting and warning of snowstorms in northwestern China, the Institute of Desert Meteorology, China Meteorological Administration, Urumqi, carried out the Central Asia Extreme Precipitation Observation Test (CAEPOT) in Yili, Xinjiang, a typical arid region in China in February 2020. This paper uses multiple fine detection datasets obtained from the CAEPOT, including radar wind profiler, ground-based microwave radiometer, and millimeter-wave cloud radar to analyze macroscopic characteristics and microphysical changes of snowstorm system in Xinjiang. Studies have shown that the low trough with sufficient moisture, heat, power conditions, and weakening banded cloud system, which moved eastward from the Aral Sea to the west of Xinjiang during the snowstorm, were the key influencing system of this snowstorm. Before the snowstorm, the vertical shear of the horizontal wind field was severe, which aggravated the instability of the atmosphere, and there was upward motion in the lower atmosphere. A variety of physical quantities related to moisture showed a tendency to increase at the lower level and could be used as an early warning signal for snowstorm about 8 hours in advance, and the cloud and snow particles observed by millimeter-wave cloud radar were simultaneously developing upward and downward from 4 km, providing snowstorm warning 12 hours in advance. During the snowstorm, the horizontal wind speed and vertical speed were obviously enhanced, and the physical quantities related to moisture further increased, and, with the blocking and uplifting of the Tianshan Mountains, the snowstorm increased. The particles collided and grew while falling, resulting in a decrease in particle concentration and an increase in particle radius from high altitude to the ground, eventually resulting in near-ground reflectivity factor up to 30 dBz. In addition, reflectivity factor, physical quantities related to moisture, wind field, particle concentration, and particle radius all had a good correspondence with the beginning, end, and intensity of snowstorm, so when the physical quantities mentioned above weakened and stopped, snowstorm also weakened and stopped. In a word, this research is an important and meaningful work that provides more backgrounds and references for the forecast and warning of snowstorm in northwestern China.

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Diametrically Opposite Scaling of Extreme Precipitation and Streamflow to Temperature in South and Central Asia

Geophysical Research Letters ◽

10.1029/2020gl089386 ◽

2020 ◽

Vol 47 (17) ◽

Author(s):

Sarosh Alam Ghausi ◽

Subimal Ghosh

Keyword(s):

Central Asia ◽

Extreme Precipitation

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How do multi-scale interactions affect extreme precipitation in eastern central Asia?

Journal of Climate ◽

10.1175/jcli-d-20-0763.1 ◽

2021 ◽

pp. 1-50

Author(s):

Qianrong Ma ◽

Jie Zhang ◽

Yujun Ma ◽

Asaminew Teshome Game ◽

Zhiheng Chen ◽

...

Keyword(s):

Central Asia ◽

North Atlantic ◽

Extreme Precipitation ◽

Wave Train ◽

Stationary Wave ◽

Tianshan Mountain ◽

Stationary Waves ◽

Transient Wave ◽

Multi Scale ◽

Eastern Central Asia

AbstractThe variability of extreme precipitation in eastern Central Asia (ECA) during summer (June–August) and its corresponding mechanisms were investigated from a multi-scale synergy perspective. Extreme precipitation in ECA displayed a quasi-monopole increasing pattern with abrupt change since 2000/2001, which was likely dominated by increased high latitude North Atlantic SST anomalies as shown by diagnosed and numerical experiment results. Increased SST via adjusting the quasi-stationary wave train which related to the negative North Atlantic Oscillation and the East Atlantic/Western Russia pattern guided cyclonic anomaly in CA, deepened the Balkhash Lake trough and enhanced the moisture convergence in ECA. These anomalies also exhibited interdecadal enhancement after 2000. On the synoptic-scale, two synoptic transient wave trains correlated with extreme precipitation in ECA by amplifying the amplitude of the quasi-stationary waves and guiding transient eddies in ECA. The induced transient eddies and deepened Balkhash Lake trough strengthened positive meridional vorticity advection and local positive vorticity, which promoted ascending motions, and guided the southerly warm moisture in ECA especially after 2000. Meanwhile, additional meso-scale vortices were stimulated and strengthened near the Tianshan Mountain in front of the wave trough, which, together with the enhanced meridional circulation, further increased extreme precipitation in ECA.

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Ecosystem functional response across precipitation extremes in a sagebrush steppe

PeerJ ◽

10.7717/peerj.4485 ◽

2018 ◽

Vol 6 ◽

pp. e4485 ◽

Cited By ~ 4

Author(s):

Andrew T. Tredennick ◽

Andrew R. Kleinhesselink ◽

J. Bret Taylor ◽

Peter B. Adler

Keyword(s):

United States ◽

Soil Moisture ◽

Functional Response ◽

Community Composition ◽

Plant Community ◽

Extreme Precipitation ◽

Sagebrush Steppe ◽

Functional Responses ◽

The Relationship

Background Precipitation is predicted to become more variable in the western United States, meaning years of above and below average precipitation will become more common. Periods of extreme precipitation are major drivers of interannual variability in ecosystem functioning in water limited communities, but how ecosystems respond to these extremes over the long-term may shift with precipitation means and variances. Long-term changes in ecosystem functional response could reflect compensatory changes in species composition or species reaching physiological thresholds at extreme precipitation levels. Methods We conducted a five year precipitation manipulation experiment in a sagebrush steppe ecosystem in Idaho, United States. We used drought and irrigation treatments (approximately 50% decrease/increase) to investigate whether ecosystem functional response remains consistent under sustained high or low precipitation. We recorded data on aboveground net primary productivity (ANPP), species abundance, and soil moisture. We fit a generalized linear mixed effects model to determine if the relationship between ANPP and soil moisture differed among treatments. We used nonmetric multidimensional scaling to quantify community composition over the five years. Results Ecosystem functional response, defined as the relationship between soil moisture and ANPP, was similar among irrigation and control treatments, but the drought treatment had a greater slope than the control treatment. However, all estimates for the effect of soil moisture on ANPP overlapped zero, indicating the relationship is weak and uncertain regardless of treatment. There was also large spatial variation in ANPP within-years, which contributes to the uncertainty of the soil moisture effect. Plant community composition was remarkably stable over the course of the experiment and did not differ among treatments. Discussion Despite some evidence that ecosystem functional response became more sensitive under sustained drought conditions, the response of ANPP to soil moisture was consistently weak and community composition was stable. The similarity of ecosystem functional responses across treatments was not related to compensatory shifts at the plant community level, but instead may reflect the insensitivity of the dominant species to soil moisture. These species may be successful precisely because they have evolved life history strategies that buffer them against precipitation variability.

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