Precipitation Characteristics and Changes

2020 ◽  
pp. 25-59
Author(s):  
Hengchun Ye ◽  
Daqing Yang ◽  
Ali Behrangi ◽  
Svetlana L. Stuefer ◽  
Xicai Pan ◽  
...  
Keyword(s):  
Precipitation Characteristics

scholarly journals Morphology of Rain Clusters Influencing Rainfall Intensity over Hainan Island

2021 ◽  
Vol 13 (15) ◽  
pp. 2920
Author(s):  
Tingting Huang ◽  
Chenghui Ding ◽  
Weibiao Li ◽  
Yilun Chen
Keyword(s):  
Rain Rate ◽  
Rainfall Intensity ◽  
Hainan Island ◽  
Precipitation Measurement ◽  
Precipitation Characteristics ◽  
Northern Side ◽  
Connected Area ◽  
Positive Correlations ◽  
Global Precipitation Measurement ◽  
Global Precipitation

Continuous observations from geostationary satellites can show the morphology of precipitation cloud systems in quasi-real-time, but there are still large deviations in the inversion of precipitation. We used binary-connected area recognition technology to identify meso-β-scale rain clusters over Hainan Island from 1 June 2000 to 31 December 2018, based on Global Precipitation Measurement (GPM) Integrated Multi-satellitE Retrievals for GPM data. We defined and statistically analyzed the parameters of rain clusters to reveal the typical morphological and precipitation characteristics of rain clusters, and to explore the relationship between the parameters and rainfall intensity of rain clusters. We found that the area and long axis of rain clusters over land were larger than those over the ocean, and that continental rain clusters were usually square in shape. Rain clusters with a larger area and longer axis were concentrated on the northern side of the mountains on Hainan Island and the intensity of rain was larger on the northern and eastern sides of the mountains. The variation of continental rain clusters over time was more dramatic than the variation of oceanic clusters. The area and long axis of rain clusters was larger between 14:00 and 21:00 from April to September and the long axis of the oceanic rain clusters increased in winter. There were clear positive correlations between the area, long axis and shape of the rain clusters and the maximum rain rate. The area and long axis of continental rain clusters had a higher correlation with the rain rate than those of oceanic clusters. The establishment of a relationship between the morphology of rain clusters and precipitation helps us to understand the laws of precipitation and improve the prediction of precipitation in this region.

scholarly journals Projected future daily characteristics of African precipitation based on global (CMIP5, CMIP6) and regional (CORDEX, CORDEX-CORE) climate models

2021 ◽  
Author(s):  
Alessandro Dosio ◽  
Martin W. Jury ◽  
Mansour Almazroui ◽  
Moetasim Ashfaq ◽  
Ismaila Diallo ◽  
...  
Keyword(s):  
East Africa ◽  
Southern Africa ◽  
Climate Models ◽  
Precipitation Intensity ◽  
Regional Models ◽  
The West ◽  
Precipitation Frequency ◽  
Global Models ◽  
Dry Spells ◽  
Precipitation Characteristics

AbstractWe provide an assessment of future daily characteristics of African precipitation by explicitly comparing the results of large ensembles of global (CMIP5, CMIP6) and regional (CORDEX, CORE) climate models, specifically highlighting the similarities and inconsistencies between them. Results for seasonal mean precipitation are not always consistent amongst ensembles: in particular, global models tend to project a wetter future compared to regional models, especially over the Eastern Sahel, Central and East Africa. However, results for other precipitation characteristics are more consistent. In general, all ensembles project an increase in maximum precipitation intensity during the wet season over all regions and emission scenarios (except the West Sahel for CORE) and a decrease in precipitation frequency (under the Representative Concentration Pathways RCP8.5) especially over the West Sahel, the Atlas region, southern central Africa, East Africa and southern Africa. Depending on the season, the length of dry spells is projected to increase consistently by all ensembles and for most (if not all) models over southern Africa, the Ethiopian highlands and the Atlas region. Discrepancies exist between global and regional models on the projected change in precipitation characteristics over specific regions and seasons. For instance, over the Eastern Sahel in July–August most global models show an increase in precipitation frequency but regional models project a robust decrease. Global and regional models also project an opposite sign in the change of the length of dry spells. CORE results show a marked drying over the regions affected by the West Africa monsoon throughout the year, accompanied by a decrease in mean precipitation intensity between May and July that is not present in the other ensembles. This enhanced drying may be related to specific physical mechanisms that are better resolved by the higher resolution models and highlights the importance of a process-based evaluation of the mechanisms controlling precipitation over the region.

scholarly journals Second Phase Precipitation in As-Welded and Solution Annealed Alloy 22 Welds

2006 ◽  
Vol 128 (4) ◽  
pp. 644-647 ◽  
Author(s):  
Bassem S. El-Dasher ◽  
Sharon G. Torres
Keyword(s):  
Large Scale ◽  
Thick Plate ◽  
Electron Backscatter Diffraction ◽  
Second Phase ◽  
Solution Annealing ◽  
Annealed Alloy ◽  
Precipitation Characteristics ◽  
Alloy 22 ◽  
Tcp Phases ◽  
Backscatter Diffraction

The precipitation characteristics of tetrahedrally close-packed (TCP) phases during the welding and the subsequent solution annealing process of Alloy 22 1 1∕2in. thick plate double-U prototypical welds are investigated. Electron backscatter diffraction was used to provide large scale microstructural observation of the weld cross section, and scanning electron microscopy was used to map the location of the TCP phases. Analysis shows that TCP precipitation occurs congruent to the weld passes, with the solution annealing reducing the sizes of coarser precipitates.

scholarly journals Convection-Permitting Forecasts Initialized with Continuously Cycling Limited-Area 3DVAR, Ensemble Kalman Filter, and “Hybrid” Variational–Ensemble Data Assimilation Systems

2014 ◽  
Vol 142 (2) ◽  
pp. 716-738 ◽  
Author(s):  
Craig S. Schwartz ◽  
Zhiquan Liu
Keyword(s):  
Kalman Filter ◽  
Data Assimilation ◽  
Three Dimensional ◽  
Skill Score ◽  
Limited Area ◽  
Computational Domain ◽  
Ensemble Data Assimilation ◽  
Ensemble Data ◽  
Precipitation Characteristics ◽  
High Precipitation

Abstract Analyses with 20-km horizontal grid spacing were produced from parallel continuously cycling three-dimensional variational (3DVAR), ensemble square root Kalman filter (EnSRF), and “hybrid” variational–ensemble data assimilation (DA) systems between 0000 UTC 6 May and 0000 UTC 21 June 2011 over a domain spanning the contiguous United States. Beginning 9 May, the 0000 UTC analyses initialized 36-h Weather Research and Forecasting Model (WRF) forecasts containing a large convection-permitting 4-km nest. These 4-km 3DVAR-, EnSRF-, and hybrid-initialized forecasts were compared to benchmark WRF forecasts initialized by interpolating 0000 UTC Global Forecast System (GFS) analyses onto the computational domain. While important differences regarding mean state characteristics of the 20-km DA systems were noted, verification efforts focused on the 4-km precipitation forecasts. The 3DVAR-, hybrid-, and EnSRF-initialized 4-km precipitation forecasts performed similarly regarding general precipitation characteristics, such as timing of the diurnal cycle, and all three forecast sets had high precipitation biases at heavier rainfall rates. However, meaningful differences emerged regarding precipitation placement as quantified by the fractions skill score. For most forecast hours, the hybrid-initialized 4-km precipitation forecasts were better than the EnSRF-, 3DVAR-, and GFS-initialized forecasts, and the improvement was often statistically significant at the 95th percentile. These results demonstrate the potential of limited-area continuously cycling hybrid DA configurations and suggest additional hybrid development is warranted.

Effects of Carbon Concentration Upon Oxygen Precipitation in Cz Si

1987 ◽  
Vol 104 ◽  
Author(s):  
S. Hahn ◽  
M. Arst ◽  
K. N. Ritz ◽  
S. Shatas ◽  
H. J. Stein ◽  
...  
Keyword(s):  
Carbon Content ◽  
Carbon Concentration ◽  
High Carbon ◽  
High Carbon Content ◽  
Oxygen Precipitation ◽  
Oxygen Precipitate ◽  
High Carbon Concentration ◽  
Precipitation Characteristics ◽  
C Complex ◽  
Oxide Precipitate

ABSTRACTEffects of high carbon concentration upon oxygen precipitate formation in Cz silicon have been investigated by combining various furnace and rapid thermal annneals. Even though oxide precipitate density increases with increasing carbon levels, Cs, synchrotron radiation section topographs of processed high carbon content wafers (Cs ∼ 4ppma) exhibit Pendellosung fringes, indicating a strain free bulk state. Our optical microscopic data have also shown very few defect etch features inside the bulk. A model based upon a direct coupling of both SiO2 and Si-C complex formation reactions is used to explain rather unique oxygen precipitation characteristics in the high carbon content Cz Si materials.

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