Generation of an improved precipitation data set from multisource information over the Tibetan Plateau

2021 ◽  
Author(s):  
Zhongkun Hong ◽  
Zhongying Han ◽  
Xueying Li ◽  
Di Long ◽  
Guoqiang Tang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Mean Squared Error ◽  
Critical Role ◽  
Reanalysis Data ◽  
The Tibetan Plateau ◽  
Efficiency Coefficient ◽  
Precipitation Data ◽  
Distributed Hydrological Model ◽  
Data Set ◽  
Daily Streamflow

AbstractPrecipitation over the Tibetan Plateau (TP) known as Asia’s water tower plays a critical role in regional water and energy cycles, largely affecting water availability for downstream countries. Rain gauges are indispensable in precipitation measurement, but are quite limited in the TP that features complex terrain and the harsh environment. Satellite and reanalysis precipitation products can provide complementary information for ground-based measurements, particularly over large poorly gauged areas. Here we optimally merged gauge, satellite, and reanalysis data by determining weights of various data sources using artificial neural networks (ANNs) and environmental variables including elevation, surface pressure, and wind speed. A Multi-Source Precipitation (MSP) data set was generated at a daily timescale and a spatial resolution of 0.1° across the TP for the 1998–2017 period. The correlation coefficient (CC) of daily precipitation between the MSP and gauge observations was highest (0.74) and the root mean squared error was the second lowest compared with four other satellite products, indicating the quality of the MSP and the effectiveness of the data merging approach. We further evaluated the hydrological utility of different precipitation products using a distributed hydrological model for the poorly gauged headwaters of the Yangtze and Yellow rivers in the TP. The MSP achieved the best Nash-Sutcliffe efficiency coefficient (over 0.8) and CC (over 0.9) for daily streamflow simulations during 2004–2014. In addition, the MSP performed best over the ungauged western TP based on multiple collocation evaluation. The merging method could be applicable to other data-scarce regions globally to provide high quality precipitation data for hydrological research.

scholarly journals Bayesian Assimilation of Multiscale Precipitation Data and Sparse Ground Gauge Observations in Mountainous Areas

2019 ◽  
Vol 20 (8) ◽  
pp. 1473-1494 ◽  
Author(s):  
Yuhan Wang ◽  
Jinsong Chen ◽  
Dawen Yang
Keyword(s):  
Tibetan Plateau ◽  
Large Scale ◽  
Daily Precipitation ◽  
Tropical Rainfall Measuring Mission ◽  
Reanalysis Data ◽  
Satellite Observations ◽  
The Tibetan Plateau ◽  
Precipitation Data ◽  
Mountainous Areas ◽  
Terrain Effects

Abstract Estimating the spatial distribution of precipitation is important for understanding ecohydrological processes at catchment scales. However, this estimation is difficult in mountainous areas because ground-based observation stations are often sparsely located and do not represent the spatial variability of precipitation. In this study, we develop a Bayesian assimilation method based on data collected on the Tibetan Plateau from 1980 to 2014 to estimate monthly and daily precipitation. To accomplish this, point-scale ground meteorological observations are combined with large-scale precipitation data such as satellite observations or reanalysis data. First, we remove the terrain effects from ground observations by fitting the precipitation data as functions of elevation, and then we spatially interpolate the residuals to 5-km-resolution grids to obtain monthly and daily precipitation. Additionally, we use Tropical Rainfall Measuring Mission (TRMM) satellite observations and ERA-Interim reanalysis data. Cross-validation methods are used to evaluate our method; the results show that our method not only captures the change in precipitation with terrain but also significantly reduces the associated uncertainty. The improvements are more evident in the main river source areas on the edge of the Tibetan Plateau, where elevation changes dramatically, and in high-altitude areas, where the ground gauges are sparse compared with those in low-altitude areas. Our assimilation method is applicable to other regions and is particularly useful for mountainous watersheds where ground meteorological stations are sparse and precipitation is considerably influenced by terrain.

scholarly journals Evaluation of TRMM precipitation and its application to distributed hydrological model in Naqu River Basin of the Tibetan Plateau

2016 ◽  
Vol 48 (3) ◽  
pp. 822-839 ◽  
Author(s):  
Denghua Yan ◽  
Shaohua Liu ◽  
Tianling Qin ◽  
Baisha Weng ◽  
Chuanzhe Li ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Tibetan Plateau ◽  
River Basin ◽  
Process Model ◽  
Hydrological Model ◽  
Hydrological Processes ◽  
The Tibetan Plateau ◽  
Precipitation Data ◽  
Distributed Hydrological Model ◽  
Trmm Precipitation

The Tibetan Plateau (TP) is the roof of the world and water towers of Asia. However, research on hydrological processes is restricted by the sparse gauge network in the TP. The distributed hydrological model is an efficient tool to explore hydrological processes. Meanwhile, the spatial distribution of precipitation directly affects the precision of distributed hydrological modelling. The latest TRMM 3B42 (V7) precipitation was evaluated compared with gauge precipitation at station and basin scales in the Naqu River Basin of the TP. The results show that Tropical Rainfall Measuring Mission (TRMM) precipitation overestimated the precipitation with BIAS of 0.2; the intensity distributions of daily precipitation are consistent in the two precipitation data. TRMM precipitation was then corrected by the good linear relation between monthly areal TRMM precipitation and gauge precipitation, and applied into the Water and Energy Process model. The results indicate that the simulated streamflow using both precipitation data produce a good fit with observed streamflow, especially at monthly scale. Furthermore, the better relations between average slopes and runoff coefficients of sub-basins from the corrected TRMM precipitation-based model implies that the spatial distribution of TRMM precipitation is closer to the spatial distribution of actual precipitation, and has an advantage in driving distributed hydrological models.

scholarly journals Long term soil moisture mapping over the Tibetan Plateau using Special Sensor Microwave/Imager

2013 ◽  
Vol 10 (5) ◽  
pp. 6629-6667 ◽  
Author(s):  
R. van der Velde ◽  
M. S. Salama ◽  
T. Pellarin ◽  
M. Ofwono ◽  
Y. Ma ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Tibetan Plateau ◽  
Mean Squared Error ◽  
Potential Evapotranspiration ◽  
Radiative Transfer Model ◽  
Retrieval Algorithm ◽  
Transfer Model ◽  
The Tibetan Plateau ◽  
Data Set ◽  
Near Surface

Abstract. This paper discusses soil moisture retrievals over the Tibetan Plateau from brightness temperature (TB's) observed by the Special Sensor Microwave Imagers (SSM/I's) during warm seasons of the period from July 1987 to December 2008. The Fundamental Climate Data Record (FCDR) of F08, F11 and F13 SSM/I satellites by the Precipitation Research Group of Colorado State University is used for this study. A soil moisture retrieval algorithm is developed based on a radiative transfer model that simulates top-of-atmosphere TB's whereby effects of atmosphere are calculated from near-surface forcings obtained from a bias-corrected data set. Validation of SSM/I retrievals against in situ measurements for a two-and-half year period (225 matchups) gives a Root Mean Squared Error of 0.046 m3 m−3. The agreement between retrievals and Noah simulations from the Global Land Data Assimilation System (GLDAS) is investigated to further provide confidence in the reliability of SSM/I retrievals at the plateau-scale. Normalized soil moisture anomalies (N) are computed on an annual and monthly basis to analyze the trends present within the products available for July 1987 to December 2008. The slope of linear regression functions between N and time is used to quantify the trends. Both the annual and monthly N indicate severe wettings of 0.8 to almost 1.6 decade−1 in the center of the plateau. Correlations are found of the trend with elevation on an annual basis and for the months May, September and October. The observed wetting of the Tibetan Plateau agrees with recent findings of permafrost retreat, precipitation increase and potential evapotranspiration decline.

scholarly journals <sup>10</sup>Be systematics in the Tsangpo-Brahmaputra catchment: the cosmogenic nuclide legacy of the eastern Himalayan syntaxis

2017 ◽  
Author(s):  
Maarten Lupker ◽  
Jérôme Lavé ◽  
Christian France-Lanord ◽  
Marcus Christl ◽  
Didier Bourlès ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Sediment Flux ◽  
Coarse Grained ◽  
The Tibetan Plateau ◽  
Data Set ◽  
Denudation Rate ◽  
Cosmogenic Nuclide ◽  
Denudation Rates ◽  
The Impact ◽  
Eastern Himalayan Syntaxis

Abstract. The Tsangpo-Brahmaputra River drains the eastern part of the Himalayan range, flowing from the Tibetan Plateau through the eastern Himalayan syntaxis and downstream to the Indo-Gangetic floodplain. As such it is a unique natural laboratory to study how denudation and sediment production processes are transferred to river detrital signals. In this study, we present a new 10Be data set to constrain denudation rates across the catchment and to quantify the impact of rapid erosion within the syntaxis region on cosmogenic nuclide budgets and signals. 10Be denudation rates span around two orders of magnitude across the catchments (ranging from 0.03 mm/yr to > 4 mm/yr) and sharply increase as the Tsangpo-Brahmaputra flows across the eastern Himalaya. The increase in denudation rates however occurs ~ 150 km downstream of the Namche Barwa-Gyala Peri massif (NBGPm), an area which has been previously characterized by extremely high erosion and exhumation rates. We suggest that this downstream lag is mainly due to the physical abrasion of coarse grained, low 10Be concentration, landslide material produced within the syntaxis that dilutes the upstream high concentration 10Be flux from the Tibetan Plateau only after abrasion has transferred sediment to the studied sand fraction. A simple abrasion model produces typical lag distances of 50 to 150 km compatible with our observations. Abrasion effects reduce the spatial resolution over which denudation can be constrained in the eastern Himalayan syntaxis. In addition, we also highlight that denudation rate estimates are dependent on the sediment connectivity, storage and quartz content of the upstream Tibetan Plateau part of the catchment which tends to lead to an overestimation of downstream denudations rates. Taking these effects into account we estimate a denudation rates of ca. 2 to 5 mm/yr for the entire syntaxis and ca. 4 to 28 mm/yr for the NBGPm, which is significantly higher than other to other large catchments. Overall, 10Be concentrations measured at the outlet of the Tsangpo-Brahmaputra in Bangladesh suggest a sediment flux between 780 and 1430 Mt/yr equivalent to a denudation rate between 0.7 and 1.2 mm/yr for the entire catchment.

scholarly journals Seasonal Features and a Case Study of Tropopause Folds over the Tibetan Plateau

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Jiali Luo ◽  
Wenjun Liang ◽  
Pingping Xu ◽  
Haiyang Xue ◽  
Min Zhang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
High Frequency ◽  
Reanalysis Data ◽  
The Tibetan Plateau ◽  
Transport Pathway ◽  
Westerly Jet ◽  
Meridional Winds ◽  
Surrounding Areas ◽  
High Potential Vorticity

Tropopause fold is the primary mechanism for stratosphere-troposphere exchange (STE) at the midlatitudes. Investigation of the features of tropopause folds over the Tibetan Plateau (TP) is important since the TP is a hotspot in global STE. In this study, we investigated seasonal features of the tropopause fold events over the TP using the 40-year ERA-Interim reanalysis data. The development of a tropopause folding case is specifically examined. The results show that shallow tropopause folds occur mostly in spring, while medium and deep folds occur mostly in winter. The multiyear mean monthly frequency of shallow tropopause folds over the TP reaches its maximum value of about 7% in May and then decreases gradually to its minimum value of 1% in August and increases again since September. Deep folds rarely occur in summer and autumn. Both the seasonal cycle and seasonal distribution of total tropopause folds over the TP are dominated by shallow folds. The relative high-frequency areas of medium and deep folds are located over the southern edge of the TP. The westerly jet movement controls the displacement of the high-frequency folding region over the TP. The region of high-frequency tropopause folds is located in the southern portion of the plateau in spring and moves northward in summer. The jet migrates back to the south in autumn and is located along about 30°N in winter, and the region where folds occur most frequently also shifts southward correspondingly. A medium fold event that occurred on 29 December 2018 is used to demonstrate the evolution of a tropopause fold case over the TP in winter; that is, the folding structure moves from west to east, the tropopause pressure is greater than 320 hPa over the folding region, while it is about 200 hPa in the surrounding areas, and the stratospheric air with high potential vorticity (PV) is transported from the high latitudes to the plateau by meridional winds. A trajectory model result verifies the transport pathway of the air parcels during the intrusion event.

scholarly journals A global climatology of stratosphere–troposphere exchange using the ERA-Interim data set from 1979 to 2011

2014 ◽  
Vol 14 (2) ◽  
pp. 913-937 ◽  
Author(s):  
B. Škerlak ◽  
M. Sprenger ◽  
H. Wernli
Keyword(s):  
North America ◽  
Tibetan Plateau ◽  
Mass Flux ◽  
West Coast ◽  
Surface Ozone ◽  
Control Surface ◽  
The Tibetan Plateau ◽  
The West ◽  
Data Set ◽  
Ozone Flux

Abstract. In this study we use the ERA-Interim reanalysis data set from the European Centre for Medium-Range Weather Forecasts (ECMWF) and a refined version of a previously developed Lagrangian methodology to compile a global 33 yr climatology of stratosphere–troposphere exchange (STE) from 1979 to 2011. Fluxes of mass and ozone are calculated across the tropopause, pressure surfaces in the troposphere, and the top of the planetary boundary layer (PBL). This climatology provides a state-of-the-art quantification of the geographical distribution of STE and the preferred transport pathways, as well as insight into the temporal evolution of STE during the last 33 yr. We confirm the distinct zonal and seasonal asymmetry found in previous studies using comparable methods. The subset of "deep STE", where stratospheric air reaches the PBL within 4 days or vice versa, shows especially strong geographical and seasonal variations. The global hotspots for deep STE are found along the west coast of North America and over the Tibetan Plateau, especially in boreal winter and spring. An analysis of the time series reveals significant positive trends of the net downward mass flux and of deep STE in both directions, which are particularly large over North America. The downward ozone flux across the tropopause is dominated by the seasonal cycle of ozone concentrations at the tropopause and peaks in summer, when the mass flux is nearly at its minimum. For the subset of deep STE events, the situation is reversed and the downward ozone flux into the PBL is dominated by the mass flux and peaks in early spring. Thus surface ozone concentration along the west coast of North America and around the Tibetan Plateau are likely to be influenced by deep stratospheric intrusions. We discuss the sensitivity of our results on the choice of the control surface representing the tropopause, the horizontal and vertical resolution of the trajectory starting grid, and the minimum residence time τ used to filter out transient STE trajectories.

scholarly journals Reducing the Statistical Distribution Error in Gridded Precipitation Data for the Tibetan Plateau

2020 ◽  
Vol 21 (11) ◽  
pp. 2641-2654
Author(s):  
Jiapei Ma ◽  
Hongyi Li ◽  
Jian Wang ◽  
Xiaohua Hao ◽  
Donghang Shao ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Interpolation Method ◽  
Mean Value ◽  
Statistical Distribution ◽  
The Tibetan Plateau ◽  
Precipitation Data ◽  
Wind Speeds ◽  
Temporal Variance ◽  
Distribution Error

AbstractGridded precipitation data are very important for hydrological and meteorological studies. However, gridded precipitation can exhibit significant statistical bias that needs to be corrected before application, especially in regions where high wind speeds, frequent snowfall, and sparse observation networks can induce significant uncertainties in the final gridded datasets. In this paper, we present a method for the production of gridded precipitation on the Tibetan Plateau (TP). This method reduces the statistical distribution error by correcting for wind-induced undercatch and optimizing the interpolation method. A gridded precipitation product constructed by this method was compared with previous products on the TP. The results show that undercatch correction is necessary for station data, which can reduce the distributional error by 30% at most. A thin-plate splines interpolation algorithm considering altitude as a covariate is helpful to reduce the statistical distributional error in general. Our method effectively inhibits the smoothing effect in gridded precipitation, and compared to previous products, results in a higher mean value, larger 98th percentile, and greater temporal variance. This study can help to improve the quality of gridded precipitation over the TP.

Lateral variation of Pn and Lg attenuation at the CDSN station LSA

1999 ◽  
Vol 89 (1) ◽  
pp. 325-330
Author(s):  
C. C. Reese ◽  
R. R. Rapine ◽  
J. F. Ni
Keyword(s):  
Tibetan Plateau ◽  
Regional Scale ◽  
The Tibetan Plateau ◽  
Lateral Variation ◽  
Data Set ◽  
Southern Boundary ◽  
Recent Tectonics ◽  
Regional Phases ◽  
Southern Tibetan Plateau ◽  
Central Tibet

Abstract The propagation efficiencies of the regional phases Lg and Pn are indicative of how active and recent tectonics influence crust and uppermost mantle properties, respectively. In this study, regional scale lateral heterogeneity of Lg and Pn attenuation for the region in and around the southern Tibetan Plateau is investigated. The data set is comprised of seismograms recorded at the Chinese Digital Seismogram Network (CDSN) station LSA from regional events with epicentral distances within 11°. Attenuation of Lg and Pn is calculated using spectral methods and assuming constant QLg and QPn models for the frequency bands 0.3 to 3.0 Hz and 0.5 to 4.0 Hz, respectively. Lateral variation in attenuation is estimated by analyzing data on an event-by-event basis. Significant lateral variation is observed with QLg decreasing from about 520 for events south of LSA to about 340 for events north of LSA and QPn ∼ 670 for southern backazimuths, while QPn ∼ 240 for northern events. For Pn, this north-south variation is consistent with other observations, indicating partially melted upper mantle beneath north central Tibet. For Lg, the azimuthal variation in attenuation indicates that Lg propagation as observed at LSA is efficient for paths crossing the southern boundary of the Tibetan Plateau relative to paths within the plateau itself.

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