scholarly journals Effects of cumulus parameterization closures on simulations of summer precipitation over the United States coastal oceans

2016 ◽  
Vol 8 (2) ◽  
pp. 764-785 ◽  
Author(s):  
Fengxue Qiao ◽  
Xin-Zhong Liang
Keyword(s):  
United States ◽  
Summer Precipitation ◽  
The United States ◽  
Cumulus Parameterization ◽  
Coastal Oceans

scholarly journals Impact of Sea Surface Temperature and Soil Moisture on Summer Precipitation in the United States Based on Observational Data

2011 ◽  
Vol 12 (5) ◽  
pp. 1086-1099 ◽  
Author(s):  
Rui Mei ◽  
Guiling Wang
Keyword(s):  
United States ◽  
Soil Moisture ◽  
Correlation Analysis ◽  
Surface Temperature ◽  
Precipitation Amount ◽  
Summer Precipitation ◽  
The United States ◽  
Sea Surface ◽  
Precipitation Prediction ◽  
The Impact

Abstract This study examines the impact of sea surface temperature (SST) and soil moisture on summer precipitation over two regions of the United States (the upper Mississippi River basin and the Great Plains) based on data from observation and observation-forced model simulations (in the case of soil moisture). Results from SST–precipitation correlation analysis show that spatially averaged SST of identified oceanic areas are better predictors than derived SST patterns from the EOF analysis and that both predictors are strongly associated with the Pacific Ocean. Results from conditioned soil moisture–precipitation correlation analysis show that the impact of soil moisture on precipitation differs between the outer-quartiles years (with summer precipitation amount in the first and fourth quartiles) and inner-quartiles years (with summer precipitation amount in the second and third quartiles), and also between the high- and low-skill SST years (categorized according to the skill of SST-based precipitation prediction). Specifically, the soil moisture–precipitation feedback is more likely to be positive and significant in the outer-quartiles years and in the years when the skill of precipitation prediction based on SST alone is low. This study indicates that soil moisture should be included as a useful predictor in precipitation prediction, and the resulting improvement in prediction skills will be especially substantial during years of large precipitation anomalies. It also demonstrates the complexity of the impact of SST and soil moisture on precipitation, and underlines the important complementary roles both SST and soil moisture play in determining precipitation.

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.

scholarly journals The hummingbird and the hawk-moth: Species distribution, geographical partitioning, and macrocompetition across the United States

2017 ◽  
Author(s):  
Abdel Halloway ◽  
Christopher J. Whelan ◽  
Joel S. Brown
Keyword(s):  
United States ◽  
Species Richness ◽  
Atmospheric Pressure ◽  
Summer Precipitation ◽  
Niche Overlap ◽  
The United States ◽  
Hawk Moth ◽  
Moth Species ◽  
Richness Patterns ◽  
Summer Time

ABSTRACTWe introduce a new concept called macrocompetition – defined as the mutual suppression of diversity/species richness of competing clades – and investigate evidence for its existence. To this end, we analyzed the distribution of two convergent nectarivorous families, hawk-moths and hummingbirds, over the continental United States to determine whether there is geographic partitioning between the families and its potential causes. Using stepwise regression, we tested for latitudinal and longitudinal biases in the species richness of both taxa and the potential role of 10 environmental variables in their distribution pattern. Hawk-moth species richness increases with longitude (eastward-bias) while that of hummingbirds declines (westward-bias). Similar geographic patterns can be seen across Canada, Mexico and South America. Hawk-moth species richness is positively correlated with higher overall temperatures (especially summer minimums), atmospheric pressure, and summer precipitation; hummingbird species richness is negatively correlated with atmospheric pressure and positively correlated with winter daily maxima. The species richness patterns reflect each family’s respective anatomical differences and support the concept of macrocompetition between the two taxa. Hawk-moth species richness was highest in states with low elevation, summer-time flowering, and warm summer nights; hummingbird species richness is highest in the southwest with higher elevation, greater cool season flowering and high daytime winter temperatures. Hawk-moths and hummingbirds as distinct evolutionary technologies exhibit niche overlap and geographical partitioning. These are two of three indicators suggested by Brown and Davidson for inter-taxonomic competition. We intend the patterns revealed here to inspire further exploration into competition and community structuring between hawk-moths and hummingbirds.

scholarly journals Projected Changes to Spring and Summer Precipitation in the Midwestern United States

2021 ◽  
Vol 3 ◽  
Author(s):  
Kevin A. Grady ◽  
Liang Chen ◽  
Trent W. Ford
Keyword(s):  
United States ◽  
Summer Precipitation ◽  
Fold Increase ◽  
The United States ◽  
Spring Precipitation ◽  
Projected Change ◽  
High Emission ◽  
Projected Changes ◽  
Precipitation Changes ◽  
Model Agreement

Spring and summer precipitation are both important factors for agricultural productivity in the Midwest region of the United States. Adequate summer precipitation, particularly in the reproductive and grain fill stages in July and August, is critical to corn and soybean success. Meanwhile, excessive spring precipitation can cause significant planting delays and introduces challenges with weed and pest management, and soil erosion and compaction. However, uncertainty especially in future summer precipitation changes, translates to uncertainties in how the joint distributions of spring and summer precipitation are expected to change by mid- and late-century across the Midwest. This study examines historical and projected changes in the characteristics of spring and summer precipitation in the Midwest using 12 dynamically downscaled simulations under the high-emission representative concentration pathway (RCP 8.5) from the NA-CORDEX project. Historical increases in spring precipitation and precipitation intensity are projected to continue into the mid- and late-century across the region, with strong model agreement. By comparison, projected changes in Midwest summer precipitation are more modest than for spring and have much less model agreement. Despite a projected three- to four-fold increase in the frequency of wet springs by late-century, relative to the model ensemble historical average, the lack of substantial and robust projected change in summer precipitation results in only a small increase in the risk of dry summers following wet springs in the Midwest by mid- and late-century.

scholarly journals Probabilistic Projections of Anthropogenic Climate Change Impacts on Precipitation for the Mid-Atlantic Region of the United States*

2012 ◽  
Vol 25 (15) ◽  
pp. 5273-5291 ◽  
Author(s):  
Liang Ning ◽  
Michael E. Mann ◽  
Robert Crane ◽  
Thorsten Wagener ◽  
Raymond G. Najjar ◽  
...  
Keyword(s):  
United States ◽  
General Circulation ◽  
Circulation Model ◽  
Summer Precipitation ◽  
Climate Change Impacts ◽  
The United States ◽  
Winter Precipitation ◽  
Specific Humidity ◽  
Atlantic Region ◽  
Projected Changes

Abstract This study uses an empirical downscaling method based on self-organizing maps (SOMs) to produce high-resolution, downscaled precipitation projections over the state of Pennsylvania in the mid-Atlantic region of the United States for the future period 2046–65. To examine the sensitivity of precipitation change to the water vapor increase brought by global warming, the authors test the following two approaches to downscaling: one uses the specific humidity in the downscaling algorithm and the other does not. Application of the downscaling procedure to the general circulation model (GCM) projections reveals changes in the relative occupancy, but not the fundamental nature, of the simulated synoptic circulation states. Both downscaling approaches predict increases in annual and winter precipitation, consistent in sign with the “raw” output from the GCMs but considerably smaller in magnitude. For summer precipitation, larger discrepancies are seen between raw and downscaled GCM projections, with a substantial dependence on the downscaling version used (downscaled precipitation changes employing specific humidity are smaller than those without it). Application of downscaling generally reduces the inter-GCM uncertainties, suggesting that some of the spread among models in the raw projected precipitation may result from differences in precipitation parameterization schemes rather than fundamentally different climate responses. Projected changes in the North Atlantic Oscillation (NAO) are found to be significantly related to changes in winter precipitation in the downscaled results, but not for the raw GCM results, suggesting that the downscaling more effectively captures the influence of climate dynamics on projected changes in winter precipitation.

scholarly journals Geographic Variation in Color, Measurements, and Molt of the Lesser Goldfinch in North America Does not Support Subspecific Designation

The Condor ◽  
2007 ◽  
Vol 109 (2) ◽  
pp. 419-436
Author(s):  
Ernest J. Willoughby
Keyword(s):  
United States ◽  
Summer Precipitation ◽  
Color Difference ◽  
The United States ◽  
Central Mexico ◽  
Geographic Variations ◽  
South Central ◽  
Color Measurements ◽  
The Pacific ◽  
Coastal Birds

Abstract I examined 963 study skins of Lesser Goldfinches (Carduelis psaltria) from the United States to central Mexico, for color, measurements, molt, and plumage wear. These specimens had been previously assigned to as many as three subspecies. Females did not vary geographically in color. Green-backed, green-eared males predominated in the Pacific coastal United States and northern Mexico. Black-backed, black-eared males predominated in the interior, east of 106° West longitude. This west to east color difference varied clinally, and may be a simple genetic polymorphism, so subspecific distinctions cannot be justified by coloration alone. Measurements of bill, tail, and wing, but not tarsus, varied slightly but significantly from smallest along the Pacific coast to largest in south-central Mexico. Since measurements varied clinally, and overlapped extensively, subspecific separation based on size is not practical. Pacific coastal birds subjected to winter rainfall maxima had a complete postbreeding molt, with a sparse prebreeding body molt only in females, and a postjuvenal molt that replaced significantly more flight feathers in males. Interior birds subjected to summer precipitation maxima had a nearly complete or complete prebreeding molt and a usually less complete postbreeding molt. The postjuvenal and postbreeding molts of interior birds were very similar and did not differ between the sexes. Although these sexual and geographic variations of molt are striking, they may reflect phenotypic plasticity in response to environmental contingencies, rather than genetic differences. These variations in one intergrading population support doubts that the Humphrey-Parkes terminology for molts and plumages can reflect phylogenetic homologies among species.

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.

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