Microphysical and Dynamical Characteristics of Low-Precipitation and Classic Supercells

2014 ◽  
Vol 71 (7) ◽  
pp. 2604-2624 ◽  
Author(s):  
Leah D. Grant ◽  
Susan C. van den Heever
Keyword(s):  
Vertical Distribution ◽  
Grid Spacing ◽  
Growth Mechanisms ◽  
Moisture Profile ◽  
Surface Precipitation ◽  
Dynamical Characteristics ◽  
Cloud Resolving Model ◽  
The Vertical Distribution ◽  
Horizontal Grid ◽  
Low Precipitation

Abstract The sensitivity of supercell morphology to the vertical distribution of moisture is investigated in this study using a cloud-resolving model with 300-m horizontal grid spacing. Simulated storms are found to transition from classic (CL) to low-precipitation (LP) supercells when the strength of elevated dry layers in the environmental moisture profile is increased. Resulting differences in the microphysical and dynamical characteristics of the CL and LPs are analyzed. The LPs produce approximately half of the accumulated surface precipitation as the CL supercell. The precipitating area in the LPs is spatially smaller and overall less intense, especially in the rear-flank downdraft region. The LPs have smaller deviant rightward storm motion compared to the CL supercell, and updrafts are narrower and more tilted, in agreement with observations. Lower relative humidities within the dry layers enhance evaporation and erode the upshear cloud edge in the LPs. This combination favors a downshear distribution of hydrometeors. As a result, hail grows preferentially along the northeastern side of the updraft in the LPs as hail embryos are advected cyclonically around the mesocyclone, whereas the primary midlevel hail growth mechanism in the CL supercell follows the classic Browning and Foote model. The differing dominant hail growth mechanisms can explain the variations in surface precipitation distribution between CLs and LPs. While large changes in the microphysical structure are seen, similarities in the structure and strength of the updraft and vorticity indicate that LP and CL supercells are not dynamically distinct storm types.

scholarly journals Evaluation of Mei-yu Heavy-Rainfall Quantitative Precipitation Forecasts in Taiwan by A Cloud-Resolving Model for Three Seasons of 2012–2014

2021 ◽  
Author(s):  
Chung-Chieh Wang ◽  
Pi-Yu Chuang ◽  
Chih-Sheng Chang ◽  
Kazuhisa Tsuboki ◽  
Shin-Yi Huang ◽  
...  
Keyword(s):  
False Alarm ◽  
Heavy Rainfall ◽  
Domain Size ◽  
Probability Of Detection ◽  
Crucial Importance ◽  
Grid Spacing ◽  
Fine Mesh ◽  
Quantitative Precipitation Forecasts ◽  
Cloud Resolving Model ◽  
Horizontal Grid

Abstract. In this study, the performance of quantitative precipitation forecasts (QPFs) by the Cloud-Resolving Storm Simulator (CReSS) in real-time in Taiwan, at a horizontal grid spacing of 2.5 km and a domain size of 1500 x 1200 km2, within a range of 72 h during three mei-yu seasons of 2012–2014 is evaluated using categorical statistics, with an emphasis on heavy events (≥ 100 mm per 24 h). The overall threat scores (TSs) of QPFs for all events on day 1 (0–24 h) are 0.18, 0.15, and 0.09 at the threshold of 100, 250, and 500 mm, respectively, and indicate considerable improvements compared to past results and 5-km models. Moreover, the TSs are shown to be higher and the model more skillful in predicting larger events, in agreement with earlier findings for typhoons. After classification based on observed rainfall, the TSs of day-1 QPFs for the largest 4 % of events by CReSS at 100, 250, and 500 mm (per 24 h) are 0.34, 0.24, and 0.16, respectively, and can reach 0.15 at 250 mm on day 2 (24–48 h) and 130 mm on day 3 (48–72 h). The larger events also exhibit higher probability of detection and lower false alarm ratio than weaker events almost without exception across all thresholds. The strength of the model lies mainly in the topographic rainfall in Taiwan rather than migratory events that are less predictable. Our results highlight the crucial importance of cloud-resolving capability and the size of fine mesh for heavy-rainfall QPFs in Taiwan.

The vertical distribution of thin features over the Arctic analysed from CALIPSO observations. Part I: Optically thin clouds

Tellus B ◽  
2011 ◽  
Vol 63 (1) ◽  
Author(s):  
Abhay Devasthale ◽  
Michael Tjernström ◽  
Karl-Göran Karlsson ◽  
Manu Anna Thomas ◽  
Colin Jones ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
The Arctic ◽  
The Vertical Distribution

scholarly journals Continuous borehole optical televiewing reveals variable englacial debris concentrations at Khumbu Glacier, Nepal

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Katie E. Miles ◽  
Bryn Hubbard ◽  
Evan S. Miles ◽  
Duncan J. Quincey ◽  
Ann V. Rowan ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Water Supply ◽  
Depth Profile ◽  
Variable Thickness ◽  
Surface Melting ◽  
High Mountain ◽  
Ablation Area ◽  
The Mean ◽  
Surface Melt ◽  
The Vertical Distribution

AbstractSurface melting of High Mountain Asian debris-covered glaciers shapes the seasonal water supply to millions of people. This melt is strongly influenced by the spatially variable thickness of the supraglacial debris layer, which is itself partially controlled by englacial debris concentration and melt-out. Here, we present measurements of deep englacial debris concentrations from debris-covered Khumbu Glacier, Nepal, based on four borehole optical televiewer logs, each up to 150 m long. The mean borehole englacial debris content is ≤ 0.7% by volume in the glacier’s mid-to-upper ablation area, and increases to 6.4% by volume near the terminus. These concentrations are higher than those reported for other valley glaciers, although those measurements relate to discrete samples while our approach yields a continuous depth profile. The vertical distribution of englacial debris increases with depth, but is also highly variable, which will complicate predictions of future rates of surface melt and debris exhumation at such glaciers.

A case study on the vertical distribution and characteristics of aerosols using ground-based raman lidar, satellite and model over Western India

2021 ◽  
Vol 42 (17) ◽  
pp. 6421-6436
Author(s):  
Sourita Saha ◽  
Som Sharma ◽  
K. Niranjan Kumar ◽  
Prashant Kumar ◽  
Vaidehi Joshi ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Western India ◽  
Raman Lidar ◽  
The Vertical Distribution

A Modified Freeze-Core Technique to Quantify the Depth Distribution of Fauna in Stony Streambeds

1983 ◽  
Vol 40 (5) ◽  
pp. 637-643 ◽  
Author(s):  
C. W. Pugsley ◽  
H. B. N. Hynes
Keyword(s):  
Vertical Distribution ◽  
Liquid Nitrogen ◽  
Benthic Invertebrates ◽  
Depth Distribution ◽  
Sampling Methods ◽  
Freezing Front ◽  
Southern Ontario ◽  
Freeze Core ◽  
Order Of Magnitude ◽  
The Vertical Distribution

A freeze-coring device using liquid nitrogen is described, which enables one person to take a columnar core, extending from the surface to at least 50 cm below a stony streambed. An experiment to validate the technique showed that animals did not flee from the advance of the freezing-front. Using frozen streambed cores, the vertical distribution of benthic invertebrates of two streams in southern Ontario was investigated. In contrast to previous estimates,~70% of the fauna was found in the top 10 cm of the streambed, and invertebrate densities were often lower by an order of magnitude. These differences are attributed to problems of quantifying previous sampling methods.

Sign in / Sign up

Export Citation Format

Share Document