Partitioning Solid and Liquid Precipitation over the Tibetan Plateau Based on Satellite Radar Observations

2021 ◽  
Author(s):  
Ping Song ◽  
Guosheng Liu
Keyword(s):  
Tibetan Plateau ◽  
Current Approach ◽  
The Tibetan Plateau ◽  
Total Precipitation ◽  
Phase Partition ◽  
Precipitation Measurement ◽  
Surface Measurements ◽  
Satellite Radar ◽  
Global Precipitation ◽  
Rainfall Estimates

AbstractWhether precipitation falls in the form of rain or snow is of great importance to glacier accumulation and ablation. Assessments of the phase-aware precipitation have been lacking over the vast area of the Tibetan Plateau (TP) due to the scarcity of surface measurements and the low quality of satellite estimates in this region. In this study, we attempt a satellite radar-based method for this precipitation partition, in which the CloudSat radar is used for snowfall while the Global Precipitation Measurement Mission radar is used for rainfall estimation. Assuming that a 11-year snowfall and a 5-year rainfall estimates represent the mean states of precipitation at each phase, the phase partition characteristics including its annual mean, spatial pattern, seasonal dependence and variation with elevations are then discussed. Averaged over the highland area (over 1 km above sea level) in TP, the annual total precipitation is estimated to be around 400 mm, of which about 40% fall as snow. The snowfall mass fraction is about 45% in the northern and 30% in the southern part of TP, and about 80% in the cold and 30% in the warm half year. Surface elevation is found to be a high-impact factor on total precipitation and its phase partition, generally with total precipitation decreasing but snowfall fraction increasing with the increase of elevation. While there are some shortcomings, the current approach in combining snowfall and rainfall estimates from two satellite radars presents a useful pathway to assessing phase-aware precipitation over the TP region.

scholarly journals Comprehensive Characteristics of Summer Deep Convection over Tibetan Plateau and Its South Slope from the Global Precipitation Measurement Core Observatory

Atmosphere ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 9 ◽  
Author(s):  
Guolu Gao ◽  
Quanliang Chen ◽  
Hongke Cai ◽  
Yang Li ◽  
Zhenglin Wang
Keyword(s):  
Tibetan Plateau ◽  
Diurnal Variation ◽  
Vertical Structure ◽  
Deep Convection ◽  
Low Frequency ◽  
The Tibetan Plateau ◽  
Precipitation Measurement ◽  
South Slope ◽  
Global Precipitation Measurement ◽  
Global Precipitation

Observational data from the Global Precipitation Measurement (GPM) Core Observatory during four summers (2014–2017) has been used to investigate deep convection systems (DCSs) over the Tibetan Plateau (TP) and its south slope (SS). The frequency, geographical distribution diurnal variation, and vertical structure of DCSs over the TP and SS are compared among these two regions. The frequency of DCSs over the SS (0.98%) was far higher than over the TP (0.15%), suggesting that stronger DCSs occur to the east and south of the TP. The maximum number of DCS occurred in July and August. A clear diurnal variation in DCS was found over the whole region, DCSs over the TP and SS both have a greatest amplitude in the afternoon. The probability of DCSs from 1200 to 1800 local time (LT) was 76.3% and 44.1% over TP and SS respectively, whereas the probability of DCSs being generated from 2200 (LT) to 0600 on the next day LT was 0.03% and 33.1% over the TP and SS respectively. There was a very low frequency of DCSs over the TP during the night. Five special echo top heights were used to investigate the vertical structure of DCSs. DCSs over the TP were both weaker and smaller than those over the SS.

scholarly journals Precipitation Retrieval over the Tibetan Plateau from the Geostationary Orbit—Part 2: Precipitation Rates with Elektro-L2 and Insat-3D

2020 ◽  
Vol 12 (13) ◽  
pp. 2114
Author(s):  
Christine Kolbe ◽  
Boris Thies ◽  
Nazli Turini ◽  
Zhiyu Liu ◽  
Jörg Bendix
Keyword(s):  
Tibetan Plateau ◽  
Rain Gauge ◽  
The Tibetan Plateau ◽  
Precipitation Measurement ◽  
Precipitation Estimates ◽  
Geo Satellites ◽  
Spatio Temporal ◽  
Model Training ◽  
Global Precipitation Measurement ◽  
Global Precipitation

We present the new Precipitation REtrieval covering the TIbetan Plateau (PRETIP) as a feasibility study using the two geostationary (GEO) satellites Elektro-L2 and Insat-3D with reference to the GPM (Global Precipitation Measurement Mission) IMERG (Integrated Multi-satellitE Retrievals for GPM) product. The present study deals with the assignment of the rainfall rate. For precipitation rate assignment, the best-quality precipitation estimates from the gauge calibrated microwave (MW) within the IMERG product were combined with the GEO data by Random Forest (RF) regression. PRETIP was validated with independent MW precipitation information not considered for model training and revealed a good performance on 30 min and 11 km spatio-temporal resolution with a correlation coefficient of R = 0.59 and outperforms the validation of the independent MW precipitation with IMERG’s IR only product (R = 0.18). A comparison of PRETIP precipitation rates in 4 km resolution with daily rain gauge measurements from the Chinese Ministry of Water Resources revealed a correlation of R = 0.49. No differences in the performance of PRETIP for various elevation ranges or between the rainy (July, August) and the dry (May, September) season could be found.

scholarly journals Evaluation and Hydrological Utility of the Latest GPM IMERG V5 and GSMaP V7 Precipitation Products over the Tibetan Plateau

2018 ◽  
Vol 10 (12) ◽  
pp. 2022 ◽  
Author(s):  
Dekai Lu ◽  
Bin Yong
Keyword(s):  
Tibetan Plateau ◽  
The Tibetan Plateau ◽  
Mountain Areas ◽  
Hydrological Simulation ◽  
Satellite Precipitation ◽  
Precipitation Measurement ◽  
Winter Snow ◽  
Comparable Performance ◽  
Global Precipitation Measurement ◽  
Global Precipitation

Satellite precipitation products provide alternative precipitation data in mountain areas. This study aimed to assess the performance of the latest Global Precipitation Measurement (GPM) Integrated Multi-satellite Retrievals for GPM (IMERG) version 5 (IMERG V5) and Global Satellite Mapping of Precipitation version 7 (GSMaP V7) products and their hydrological utilities over the Tibetan Plateau (TP). Here, two IMERG Final Run products (uncalibrated IMERG (IMERG-UC) and gauge-calibrated IMERG (IMEEG-C)) and two GSMaP products (GSMaP Moving Vector with Kalman Filter (GSMaP-MVK) and gauge-adjusted GSMaP (GSMaP-Gauge)) were evaluated from April 2014 to March 2017. Results show that all four satellite precipitation products could generally capture the spatial patterns of precipitation over the TP. The two gauge-adjusted products were more consistent with the ground measurements than the satellite-only products in terms of statistical assessment. For hydrological simulation, IMERG-UC and GSMaP-MVK showed unsatisfactory performance for hydrological utility, while GSMaP-Gauge demonstrated comparable performance with gauge reference data, suggesting that GSMaP-Gauge can be selected for hydrological application in the TP. Our study also indicates that accurately measuring light rainfall and winter snow is still a challenging task for the current satellite precipitation retrievals.

Convection permitting simulation of summer precipitation over the Tibetan Plateau

2021 ◽  
Author(s):  
Zhaoyang Liu ◽  
Yanhong Gao
Keyword(s):  
Water Resources ◽  
Tibetan Plateau ◽  
Water Cycle ◽  
Global Climate ◽  
Summer Precipitation ◽  
The Tibetan Plateau ◽  
Hydrological Process ◽  
Diurnal Cycles ◽  
Precipitation Measurement ◽  
Global Precipitation

<p>The Tibetan Plateau (TP), known as the "Third Pole" and "Water Tower of Asia", plays an essential role in the regional water cycle and global climate change through its unique topography and abundant water resources. Precipitation is an important part of the hydrological process, but realistically simulating precipitation over the TP is still a major challenge for most models, which hinders our understanding of the strength of the land-atmosphere interaction and its influences on regional, or even global climate and water cycle. In order to better depict precipitation spatial and temporal distributions over the TP, a 4-km convection permitting modelling (CPM) and a 28-km dynamical downscale modelling (DDM) using the weather Research and Forecasting model (WRF) were conducted for a summer (from June to August 2014). WRF simulations are evaluated against CMA in-situ observations, the Asian Precipitation Highly Resolved Observational Data Integration Towards Evaluation of water resources (APHRODITE), the Global Precipitation Measurement (GPM), as well as two reanalysis datasets ERA-Interim and ERA5. We focus on the added values of the CPM in summer precipitation simulations, in terms of the spatial seasonal mean precipitation amounts, spatial distributions, and diurnal cycles. We found the six datasets (CPM, DDM, APHRODITE, GPM, ERA-Interim and ERA5) showed great differences in summer precipitation over the TP. The great advantages of CPM and DDM over reanalyses are observed. Slight improvements are found in CPM over DDM as well. Mechanisms for these differences will be explored.</p>

Precipitation Retrieval over the Tibetan Plateau from the Geostationary Orbit

2020 ◽  
Author(s):  
Christine Kolbe ◽  
Boris Thies ◽  
Nazli Turini ◽  
Jörg Bendix
Keyword(s):  
Tibetan Plateau ◽  
The Tibetan Plateau ◽  
Cloud Properties ◽  
Spectral Bands ◽  
Precipitation Measurement ◽  
High Asia ◽  
Precipitation Estimates ◽  
Optimization Schemes ◽  
Global Precipitation Measurement ◽  
Global Precipitation

<p>The distribution of precipitation on the Tibetan Plateau (TiP) is not yet understood due to various factors. Satellite-based precipitation retrieval can provide comprehensive information in a high spatial-temporal resolution. The aim of this feasibility study is to retrieve precipitation rates over High Asia using multi-spectral data from the two geostationary (GEO) satellites Elektro-L2 and Insat-3D in a 30 minutes and 4 km resolution. The variety of spectral bands from both satellites provides an insight into the cloud properties which are associated with precipitation. In the first step, the precipitation area is delineated, and in a second step, the rates are retrieved. To this end, we use a machine learning approach (Random Forest, RF) and a precipitation product of the Global Precipitation Measurement Mission (GPM IMERG) as a reference. From this product, we use the best quality gauge calibrated microwave (MW) precipitation estimates. We validate our results with independent gauge calibrated MW precipitation. To improve the RF models, we tested various optimization schemes. The results of this study will provide information about the precipitation processes in High Asia.</p>

scholarly journals Comparisons of Spatially Downscaling TMPA and IMERG over the Tibetan Plateau

2018 ◽  
Vol 10 (12) ◽  
pp. 1883 ◽  
Author(s):  
Ziqiang Ma ◽  
Kang He ◽  
Xiao Tan ◽  
Jintao Xu ◽  
Weizhen Fang ◽  
...  
Keyword(s):  
Random Forest ◽  
Tibetan Plateau ◽  
Spatial Information ◽  
Rain Gauge ◽  
The Tibetan Plateau ◽  
Precipitation Data ◽  
Precipitation Measurement ◽  
Precipitation Estimates ◽  
Improved Accuracy ◽  
Global Precipitation

Accurate precipitation data is crucial in many applications such as hydrology, meteorology, and ecology. Compared with ground observations, satellite-based precipitation estimates can provide much more spatial information to characterize precipitation. In this study, the satellite-based precipitation products of Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (IMERG) and Tropical Rainfall Measurement Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) were firstly evaluated over the Tibetan Plateau (TP) in 2015 against ground observations at both annual and monthly scales. Secondly, random forest algorithm was used to obtain the annual downscaled results (~1 km) based on IMERG and TMPA data and the downscaled results were examined against rain gauge data. Thirdly, a disaggregation algorithm was used to obtain the monthly downscaled results based on those at annual scale. The results indicated that (1) IMERG performed better than TMPA at both annual and monthly scales; (2) IMERG had few anomalies while TMPA displayed significant numbers of outliers in central and western parts of the TP; (3) random forest was a promising algorithm in acquiring high resolution precipitation data with improved accuracy; (4) the downscaled results based on IMERG had better performances than those based on TMPA.

scholarly journals GPM Satellite Radar Observations of Precipitation Mechanisms in Atmospheric Rivers

2020 ◽  
Vol 148 (4) ◽  
pp. 1449-1463 ◽  
Author(s):  
Forest Cannon ◽  
Jason M. Cordeira ◽  
Chad W. Hecht ◽  
Joel R. Norris ◽  
Allison Michaelis ◽  
...  
Keyword(s):  
Water Cycle ◽  
Global Scale ◽  
Convective Precipitation ◽  
Dual Frequency ◽  
Atmospheric Rivers ◽  
Precipitation Measurement ◽  
Precipitation Processes ◽  
Thermodynamic Conditions ◽  
Satellite Radar ◽  
Global Precipitation

Abstract Despite numerous studies documenting the importance of atmospheric rivers (AR) to the global water cycle and regional precipitation, the evolution of their water vapor fluxes has been difficult to investigate given the challenges of observing and modeling precipitation processes within ARs over the ocean. This study uses satellite-based radar reflectivity profiles from the Global Precipitation Measurement Dual-Frequency Precipitation Radar (GPM-DPR), combined with kinematic and thermodynamic conditions in the vicinity of the precipitation diagnosed from the Climate Forecast System Reanalysis, to evaluate the characteristics and dynamical origins of precipitation in ARs over the northeast Pacific Ocean. Transects of 192 ARs between 2014 and 2018 are examined. Both stratiform and convective precipitation were abundant in these GPM transects and the precipitation was most often generated by forced ascent in the vicinity of a cold front in frontogenetic environments. Conditioning composite vertical profiles of reflectivity and latent heating from GPM-DPR on frontogenesis near the moist-neutral low-level jet demonstrated the importance of frontally forced precipitation on atmospheric heating tendencies. A case study of a high-impact landfalling AR is analyzed using the Weather Research and Forecasting Model, which showed how the precipitation processes and subsequent latent heat release offshore strongly influenced AR evolution. Although these precipitation mechanisms are present in global-scale models, the difficulty that coarse-resolution models have in accurately representing resultant precipitation likely translates to uncertainty in forecasting heating tendencies, their feedbacks on AR evolution, and ultimately the impacts of ARs upon landfall in the western United States.

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