scholarly journals Changing Frequency of Heavy Rainfall over the Central United States

2013 ◽  
Vol 26 (1) ◽  
pp. 351-357 ◽  
Author(s):  
Gabriele Villarini ◽  
James A. Smith ◽  
Gabriel A. Vecchi
Keyword(s):  
United States ◽  
Heavy Rainfall ◽  
Daily Rainfall ◽  
Rain Gauge ◽  
First Century ◽  
Temperature Record ◽  
Central United States ◽  
Increasing Trends ◽  
Surface Temperature Record ◽  
Threshold Approach

Abstract Records of daily rainfall accumulations from 447 rain gauge stations over the central United States (Minnesota, Wisconsin, Michigan, Iowa, Illinois, Indiana, Missouri, Kentucky, Tennessee, Arkansas, Louisiana, Alabama, and Mississippi) are used to assess past changes in the frequency of heavy rainfall. Each station has a record of at least 50 yr, and the data cover most of the twentieth century and the first decade of the twenty-first century. Analyses are performed using a peaks-over-threshold approach, and, for each station, the 95th percentile is used as the threshold. Because of the count nature of the data and to account for both abrupt and slowly varying changes in the heavy rainfall distribution, a segmented regression is used to detect changepoints at unknown points in time. The presence of trends is assessed by means of a Poisson regression model to examine whether the rate of occurrence parameter is a linear function of time (by means of a logarithmic link function). The results point to increasing trends in heavy rainfall over the northern part of the study domain. Examination of the surface temperature record suggests that these increasing trends occur over the area with the largest increasing trends in temperature and, consequently, with an increase in atmospheric water vapor.

scholarly journals A Comparison Between Global Satellite Mapping of Precipitation Data and High-Resolution Radar Data – A Case Study of Localized Torrential Rainfall over Japan

2021 ◽  
Vol 16 (4) ◽  
pp. 786-793
Author(s):  
Yoshiaki Hayashi ◽  
Taichi Tebakari ◽  
Akihiro Hashimoto ◽  
◽  
Keyword(s):  
High Resolution ◽  
Heavy Rainfall ◽  
Daily Rainfall ◽  
Radar Data ◽  
Rain Gauge ◽  
Hourly Rainfall ◽  
The Difference ◽  
Microwave Imager ◽  
Satellite Mapping

This paper presents a case study comparing the latest algorithm version of Global Satellite Mapping of Precipitation (GSMaP) data with C-band and X-band Multi-Parameter (MP) radar as high-resolution rainfall data in terms of localized heavy rainfall events. The study also obliged us to clarify the spatial and temporal resolution of GSMaP data using high-accuracy ground-based radar, and evaluate the performance and reporting frequency of GSMaP satellites. The GSMaP_Gauge_RNL data with less than 70 mm/day of daily rainfall was similar to the data of both radars, but the GSMaP_Gauge_RNL data with over 70 mm/day of daily rainfall was not, and the calibration by rain-gauge data was poor. Furthermore, both direct/indirect observations by the Global Precipitation Measurement/Microwave Imager (GPM/GMI) and the frequency thereof (once or twice) significantly affected the difference between GPM/GMI data and C-band radar data when the daily rainfall was less than 70 mm/day and the hourly rainfall was less than 20 mm/h. Therefore, it is difficult for GSMaP_Gauge to accurately estimate localized heavy rainfall with high-density particle precipitation.

scholarly journals Assessing the Evolution of Soil Moisture and Vegetation Conditions during a Flash Drought–Flash Recovery Sequence over the South-Central United States

2019 ◽  
Vol 20 (3) ◽  
pp. 549-562 ◽  
Author(s):  
Jason A. Otkin ◽  
Yafang Zhong ◽  
Eric D. Hunt ◽  
Jeff Basara ◽  
Mark Svoboda ◽  
...  
Keyword(s):  
United States ◽  
Soil Moisture ◽  
Land Surface ◽  
Heavy Rainfall ◽  
Recovery Period ◽  
The South ◽  
Recovery Sequence ◽  
Near Surface ◽  
South Central ◽  
Central United States

Abstract This study examines the evolution of soil moisture, evapotranspiration, vegetation, and atmospheric conditions during an unusual flash drought–flash recovery sequence that occurred across the south-central United States during 2015. This event was characterized by a period of rapid drought intensification (flash drought) during late summer that was terminated by heavy rainfall at the end of October that eliminated the extreme drought conditions over a 2-week period (flash recovery). A detailed analysis was performed using time series of environmental variables derived from meteorological, remote sensing, and land surface modeling datasets. Though the analysis revealed a similar progression of cascading effects in each region, characteristics of the flash drought such as its onset time, rate of intensification, and vegetation impacts differed between regions due to variations in the antecedent conditions and the atmospheric anomalies during its growth. Overall, flash drought signals initially appeared in the near-surface soil moisture, followed closely by reductions in evapotranspiration. Total column soil moisture deficits took longer to develop, especially in the western part of the region where heavy rainfall during the spring and early summer led to large moisture surpluses. Large differences were noted in how land surface models in the North American Land Data Assimilation System depicted soil moisture evolution during the flash drought; however, the models were more similar in their assessment of conditions during the flash recovery period. This study illustrates the need to use multiple datasets to track the evolution and impacts of rapidly evolving flash drought and flash recovery events.

Increasing Frequency of Flood Events across the Central United States: A Weather-Type Perspective

2020 ◽  
Author(s):  
Gabriele Villarini ◽  
Wei Zhang
Keyword(s):  
United States ◽  
Large Scale ◽  
Weather Type ◽  
Jet Stream ◽  
Flood Events ◽  
Weather Types ◽  
Study Region ◽  
Central United States ◽  
Upper Level ◽  
Increasing Trends

<p>The frequency of flood events has been increasing across large areas of the central United States since the second half of the 20<sup>th</sup> century; these increasing trends have been largely related to changes in precipitation. The aim of this presentation is to provide insights into the possible reasons responsible for these changes, providing basic information that may enhance our capability of predicting and projecting these changes.</p><p>This study highlights the role of weather types in explaining the observed changes in precipitation and, consequently, in the frequency of flood events. More specifically, we identify five weather types from daily 500-hPa geopotential height using the k-means cluster analysis. Consistent with their distinct large-scale atmospheric patterns, these weather types exert different effects on precipitation in the central United States. Because of the strong moisture transport, strengthened low-level jet stream and wavy upper-level polar jet stream located in the western United States, among the five weather types weather-type 1 exerts the strongest impacts on precipitation, accounting for up to 40% of the total precipitation over the study region. Moreover, we detect a significant upward trend in the number and persistency of these two weather types for 1948–2019, suggesting a rising risk of heavy and long-lasting precipitation across the central United States.</p>

scholarly journals The Relationship between the Pacific–North American Teleconnection Pattern, the Great Plains Low-Level Jet, and North Central U.S. Heavy Rainfall Events*

2015 ◽  
Vol 28 (17) ◽  
pp. 6729-6742 ◽  
Author(s):  
Keith J. Harding ◽  
Peter K. Snyder
Keyword(s):  
United States ◽  
Great Plains ◽  
Heavy Rainfall ◽  
Teleconnection Pattern ◽  
North Central ◽  
Rainfall Events ◽  
The North ◽  
The Pacific ◽  
Central United States ◽  
Heavy Rainfall Events

Abstract This study demonstrates the relationship between the Pacific–North American (PNA) teleconnection pattern and the Great Plains low-level jet (GPLLJ). The negative phase of the PNA, which is associated with lower heights over the Great Plains and ridging in the southeastern United States, enhances the GPLLJ by increasing the pressure gradient within the GPLLJ on 6-hourly to monthly time scales. Strong GPLLJ events predominantly occur when the PNA is negative. Warm-season strong GPLLJ events with a very negative PNA (<−1) are associated with more persistent, longer wavelength planetary waves that increase the duration of GPLLJ events and enhance precipitation over the north central United States. When one considers the greatest 5-day north central U.S. precipitation events, a large majority occur when the PNA is negative, with most exhibiting a very negative PNA. Stronger moisture transport during heavy rainfall events with a very negative PNA decreases the precipitation of locally derived moisture compared to events with a very positive PNA. The PNA becomes negative 2–12 days before heavy rainfall events and is very negative within two weeks of 78% of heavy rainfall events in the north central United States, a finding that could be used to improve medium-range forecasts of heavy rainfall events.

scholarly journals Composites of Heavy Rain Producing Elevated Thunderstorms in the Central United States

2017 ◽  
Vol 2017 ◽  
pp. 1-19 ◽  
Author(s):  
Laurel P. McCoy ◽  
Patrick S. Market ◽  
Chad M. Gravelle ◽  
Charles E. Graves ◽  
Neil I. Fox ◽  
...  
Keyword(s):  
United States ◽  
Heavy Rainfall ◽  
Warm Season ◽  
Heavy Rain ◽  
The United States ◽  
Large Variability ◽  
Null Case ◽  
Central United States ◽  
Mean Fields ◽  
Event Occurrence

Composite analyses of the atmosphere over the central United States during elevated thunderstorms producing heavy rainfall are presented. Composites were created for five National Weather Service County Warning Areas (CWAs) in the region. Events studied occurred during the warm season (April–September) during 1979–2012. These CWAs encompass the region determined previously to experience the greatest frequency of elevated thunderstorms in the United States. Composited events produced rainfall of >50 mm 24 hr−1 within the selected CWA. Composites were generated for the 0–3 hr period prior to the heaviest rainfall, 6–9 hours prior to it, and 12–15 hours prior to it. This paper focuses on the Pleasant Hill, Missouri (EAX) composites, as all CWA results were similar; also these analyses focus on the period 0–3 hours prior to event occurrence. These findings corroborate the findings of previous authors. What is offered here that is unique is (1) a measure of the interquartile range within the composite mean fields, allowing for discrimination between variable fields that provided a strong reliable signal, from those that may appear strong but possess large variability, and (2) composite soundings of two subclasses of elevated thunderstorms. Also, a null case (one that fits the composite but failed to produce significant rainfall) is also examined for comparison.

scholarly journals Synoptic environment associated with heavy rainfall events on the coastland of Northeast Brazil

2013 ◽  
Vol 35 ◽  
pp. 73-78 ◽  
Author(s):  
P. T. Oliveira ◽  
K. C. Lima ◽  
C. M. Santos e Silva
Keyword(s):  
Coastal Area ◽  
Heavy Rainfall ◽  
Daily Rainfall ◽  
South Atlantic Convergence Zone ◽  
Rain Gauge ◽  
Economic Losses ◽  
Heavy Rainfall Event ◽  
Northeast Brazil ◽  
Daily Data ◽  
Upper Level

Abstract. Northeast Brazil (NEB) has an extensive coastal area, often hit by natural disasters that bring many social and economic losses. The objective of this work was to study the synoptic environment associated with a heavy rainfall event (HRE) on the coastland of NEB. We used daily rainfall data for coastal area of NEB between the states of Rio Grande do Norte and Bahia, divided into two subregions: north and south coastland. This data was obtained from the hydrometeorological network managed by the Agência Nacional de Águas and the daily data reanalysis from the ERAInterim. For the selection of HRE the technique of quantiles was used, thus defined HRE where at least one rain gauge recorded rainfall above 95th percentile. The interannual distribution of events showed occurrence maximum in La Niña years and minimal in El Niño years. The results suggest that the HRE were formed mainly due to the action of upper-level cyclonic vortex, in hight levels, and due to the action to South Atlantic convergence zone, in low levels.

scholarly journals Projections of heavy rainfall over the central United States based on CMIP5 models

2013 ◽  
Vol 14 (3) ◽  
pp. 200-205 ◽  
Author(s):  
Gabriele Villarini ◽  
Enrico Scoccimarro ◽  
Silvio Gualdi
Keyword(s):  
United States ◽  
Heavy Rainfall ◽  
Cmip5 Models ◽  
Central United States
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