Analysis of watershed topography effects on summer precipitation variability in the southwestern United States

2014 ◽  
Vol 511 ◽  
pp. 838-849 ◽  
Author(s):  
Dagbegnon C. Sohoulande Djebou ◽  
Vijay P. Singh ◽  
Oliver W. Frauenfeld
Keyword(s):  
United States ◽  
Summer Precipitation ◽  
Precipitation Variability ◽  
Southwestern United States

SST–North American Hydroclimate Links in AMIP Simulations of the Drought Working Group Models: A Proxy for the Idealized Drought Modeling Experiments

2010 ◽  
Vol 23 (10) ◽  
pp. 2585-2598 ◽  
Author(s):  
Alfredo Ruiz-Barradas ◽  
Sumant Nigam
Keyword(s):  
United States ◽  
Great Plains ◽  
Working Group ◽  
Climate Model ◽  
Linear Trend ◽  
Summer Precipitation ◽  
The United States ◽  
Precipitation Variability ◽  
Drought Severity ◽  
Model Experiments

Abstract The present study assesses the potential of the U.S. Climate Variability and Predictability (CLIVAR) Drought Working Group (DWG) models in simulating interannual precipitation variability over North America, especially the Great Plains. It also provides targets for the idealized DWG model experiments investigating drought origin. The century-long Atmospheric Model Intercomparison Project (AMIP) simulations produced by version 3.5 of NCAR’s Community Atmosphere Model (CAM3.5), the Lamont-Doherty Earth Observatory’s Community Climate Model (CCM3), and NASA’s Seasonal-to-Interannual Prediction Project (NSIPP-1) atmospheric models are analyzed; CCM3 and NSIPP-1 models have 16- and 14-ensemble simulations, respectively, while CAM3.5 only has 1. The standard deviation of summer precipitation is different in AMIP simulations. The maximum over the central United States seen in observations is placed farther to the west in simulations. Over the central plains the models exhibit modest skill in simulating low-frequency precipitation variability, a Palmer drought severity index proxy. The presence of a linear trend increases correlations in the period 1950–99 when compared with those for the whole century. The SST links of the Great Plains drought index have features in common with observations over both the Pacific and Atlantic Oceans. Interestingly, summer-to-fall precipitation regressions of the warm Trend, cold Pacific, and warm Atlantic modes of annual mean SST variability (used in forcing the DWG idealized model experiments) tend to dry the southwestern, midwestern, and southeastern regions of the United States in the observations and, to a lesser extent, in the simulations. The similarity of the idealized SST-forced droughts in DWG modeling experiments with AMIP precipitation regressions of the corresponding SST principal components, evident especially in the case of the cold Pacific pattern, suggests that the routinely conducted AMIP simulations could have served as an effective proxy for the more elaborated suite of DWG modeling experiments.

Great Plains Precipitation and Its SST Links in Twentieth-Century Climate Simulations, and Twenty-First- and Twenty-Second-Century Climate Projections

2010 ◽  
Vol 23 (23) ◽  
pp. 6409-6429 ◽  
Author(s):  
Alfredo Ruiz-Barradas ◽  
Sumant Nigam
Keyword(s):  
United States ◽  
Twentieth Century ◽  
Great Plains ◽  
Summer Precipitation ◽  
Precipitation Variability ◽  
Second Century ◽  
First Century ◽  
Climate Simulations ◽  
Central United States ◽  
Twenty First Century

Abstract The present work assesses spring and summer precipitation over North America as well as summer precipitation variability over the central United States and its SST links in simulations of the twentieth-century climate and projections of the twenty-first- and twenty-second-century climates for the A1B scenario. The observed spatial structure of spring and summer precipitation poses a challenge for models, particularly over the western and central United States. Tendencies in spring precipitation in the twenty-first century agree with the observed ones at the end of the twentieth century over a wetter north-central and a drier southwestern United States, and a drier southeastern Mexico. Projected wetter springs over the Great Plains in the twenty-first and twenty-second centuries are associated with an increase in the number of extreme springs. In contrast, projected summer tendencies have demonstrated little consistency. The associated observed changes in SSTs bear the global warming footprint, which is not well captured in the twentieth-century climate simulations. Precipitation variability over the Great Plains presents a coherent picture in spring but not in summer. Models project an increase in springtime precipitation variability owing to an increased number of extreme springs. The number of extreme droughty (pluvial) events during the spring–fall part of the year is under(over)estimated in the twentieth century without consistent projections. Summer precipitation variability over the Great Plains is linked to SSTs over the Pacific and Atlantic Oceans, with no apparent ENSO link in spite of the exaggerated variability in the equatorial Pacific in climate simulations; this has been identified already in observations and atmospheric models forced with historical SSTs. This link is concealed due to the increased warming in the twenty-first century. Deficiencies in land surface–atmosphere interactions and global teleconnections in the climate models prevent them from a better portrayal of summer precipitation variability in the central United States.

scholarly journals Contribution of Cutoff Lows to Precipitation across the United States

2016 ◽  
Vol 55 (4) ◽  
pp. 893-899 ◽  
Author(s):  
John T. Abatzoglou
Keyword(s):  
United States ◽  
Great Plains ◽  
Summer Precipitation ◽  
The United States ◽  
Precipitation Variability ◽  
Western United States ◽  
Spring Precipitation ◽  
Mountain Ranges ◽  
Extreme Precipitation Events ◽  
Slow Moving

AbstractA chronology of cutoff lows (COL) from 1979 to 2014 alongside daily precipitation observations across the conterminous United States was used to examine the contribution of COL to seasonal precipitation, extreme-precipitation events, and interannual precipitation variability. COL accounted for between 2% and 32% of annual precipitation at stations across the United States, with distinct geographic and seasonal variability. The largest fractional contribution of COL to precipitation totals and precipitation extremes was found across the Great Plains and the interior western United States, particularly during the transition seasons of spring and autumn. Widespread significant correlations between seasonal COL precipitation and total precipitation on interannual time scales were found across parts of the United States, most notably to explain spring precipitation variability in the interior western United States and Great Plains and summer precipitation variability in the northwestern United States. In addition to regional differences, a distinct gradient in the contributions of COL to precipitation was found in the lee of large mountain ranges in the western United States. Differences in orographic precipitation enhancement associated with slow-moving COL resulted in relatively more precipitation at lower elevations and, in particular, east of north–south-oriented mountain ranges that experience a strong rain shadow with progressive disturbances.

Sign in / Sign up

Export Citation Format

Share Document