A Brief Evaluation of Precipitation from the North American Regional Reanalysis

2007 ◽  
Vol 8 (4) ◽  
pp. 837-846 ◽  
Author(s):  
Melissa S. Bukovsky ◽  
David J. Karoly
Keyword(s):  
United States ◽  
Spatial Distribution ◽  
Diurnal Cycle ◽  
Annual Cycle ◽  
North American ◽  
The United States ◽  
The Other ◽  
The North ◽  
North American Regional Reanalysis ◽  
Regional Reanalysis

Abstract Several aspects of the precipitation climatology from the North American Regional Reanalysis (NARR) are analyzed and compared with two other reanalyses and one set of gridded observations over a domain encompassing the United States. The spatial distribution, diurnal cycle, and annual cycle of precipitation are explored to establish the reliability of the reanalyses and to judge their usefulness. While the NARR provides a much improved representation of precipitation over that of the other reanalyses examined, some inaccuracies are found and have been highlighted as a warning to potential users of the data.

scholarly journals Representation of Terrestrial Hydrology and Large-Scale Drought of the Continental United States from the North American Regional Reanalysis

2012 ◽  
Vol 13 (3) ◽  
pp. 856-876 ◽  
Author(s):  
Justin Sheffield ◽  
Ben Livneh ◽  
Eric F. Wood
Keyword(s):  
United States ◽  
Soil Moisture ◽  
North American ◽  
Land Surface ◽  
Large Scale ◽  
State Of The Art ◽  
Vic Model ◽  
The North ◽  
North American Regional Reanalysis ◽  
Regional Reanalysis

Abstract The North American Regional Reanalysis (NARR) is a state-of-the-art land–atmosphere reanalysis product that provides improved representation of the terrestrial hydrologic cycle compared to previous global reanalyses, having the potential to provide an enhanced picture of hydrologic extremes such as floods and droughts and their driving mechanisms. This is partly because of the novel assimilation of observed precipitation, state-of-the-art land surface scheme, and higher spatial resolution. NARR is evaluated in terms of the terrestrial water budget and its depiction of drought at monthly to annual time scales against two offline land surface model [Noah v2.7.1 and Variable Infiltration Capacity (VIC)] simulations and observation-based runoff estimates over the continental United States for 1979–2003. An earlier version of the Noah model forms the land component of NARR and so the offline simulation provides an opportunity to diagnose NARR land surface variables independently of atmospheric feedbacks. The VIC model has been calibrated against measured streamflow and so provides a reasonable estimate of large-scale evapotranspiration. Despite similar precipitation, there are large differences in the partitioning of precipitation into evapotranspiration and runoff. Relative to VIC, NARR and Noah annual evapotranspiration is biased high by 28% and 24%, respectively, and the runoff ratios are 50% and 40% lower. This is confirmed by comparison with observation-based runoff estimates from 1130 small, relatively unmanaged basins across the continental United States. The overestimation of evapotranspiration by NARR is largely attributed to the evapotranspiration component of the Noah model, whereas other factors such as atmospheric forcings or biases induced by precipitation assimilation into NARR play only a minor role. A combination of differences in the parameterization of evapotranspiration and in particular low stomatal resistance values in NARR, the seasonality of vegetation characteristics, the near-surface radiation and meteorology, and the representation of soil moisture dynamics, including high infiltration rates and the relative coupling of soil moisture with baseflow in NARR, are responsible for the differences in the water budgets. Large-scale drought as quantified by soil moisture percentiles covaries closely over the continental United States between the three datasets, despite large differences in the seasonal water budgets. However, there are large regional differences, especially in the eastern United States where the VIC model shows higher variability in drought dynamics. This is mostly due to increased frequency of completely dry conditions in NARR that result from differences in soil depth, higher evapotranspiration, early snowmelt, and early peak runoff. In the western United States, differences in the precipitation forcing contribute to large discrepancies between NARR and Noah/VIC simulations in the representation of the early 2000s drought.

scholarly journals Poder e Autonomia: As Assimetrias do Sistema Financeiro e Monetário Internacional

2018 ◽  
Vol 2 (1) ◽  
pp. 104-123
Author(s):  
Gabriel Santos Carneiro
Keyword(s):  
United States ◽  
Latin American ◽  
North American ◽  
Debt Crisis ◽  
The United States ◽  
The Other ◽  
The North ◽  
Monetary Relations ◽  
Match Theory ◽  
Latin American Countries

Este artigo tem por objetivo explicitar a natureza assimétrica das relações financeiras e monetárias entre os Estados desde 1945 até o presente. Destaca-se que as decisões tomadas acerca das questão financeiras internacionais foram marcadas pelo unilateralismo dos Estados Unidos, de forma que o poder, tratado em termos de autonomia, se mostrou fator decisivo e explicativo das mudanças financeiras internacionais. Assim, o sistema financeiro internacional é caracterizado por uma discrepante autonomia norte-americana em relação aos demais países, de maneira que esse sistema é moldado fundamentalmente a partir dos interesses dos Estados Unidos, enquanto que aos demais Estados restam as consequências, em larga medida desfavoráveis, das opções escolhidas. O artigo, com o objetivo de casar a teoria com a história, focará em dois eventos específicos: a crise da libra esterlina de 1947 e a crise da dívida dos países latino-americanos da década de 1980, buscando sempre mostrar como que as ações norte-americanas acabam por prejudicar e afetar negativamente os demais Estados que carecem de autonomia para resistirem às influências externas.  This article aims to explain the asymmetric nature of financial and monetary relations between States since 1945 until nowadays. It is highlighted that the decisions made on the international financial matters are characterized by the unilateralism of the United States, in a way that power, seen here as autonomy, has proven to be a decisive and explanatory element of the international financial changes. Thus, the international financial system is characterized by a discrepant North-American autonomy compared to other countries, so that this system is fundamentally forged under the interests of the United States, whereas the consequences from the chosen choices, which are mainly negative, are left for the other countries. The article, intending to match theory with history, will focus in two specific events: the 1947’s sterling crisis and the 1980s external debt crisis of the Latin-American countries, looking forward to demonstrate how the North-American actions impaired and undermined the other countries that lack autonomy to resist external influences.  

scholarly journals Understanding the Characteristics of Daily Precipitation over the United States Using the North American Regional Reanalysis

2009 ◽  
Vol 22 (23) ◽  
pp. 6268-6286 ◽  
Author(s):  
Emily J. Becker ◽  
Ernesto Hugo Berbery ◽  
R. Wayne Higgins
Keyword(s):  
United States ◽  
Extreme Events ◽  
Daily Precipitation ◽  
Precipitable Water ◽  
Moisture Flux ◽  
The United States ◽  
Moisture Flux Convergence ◽  
The North ◽  
North American Regional Reanalysis ◽  
Regional Reanalysis

Abstract This study examines the seasonal characteristics of daily precipitation over the United States using the North American Regional Reanalysis (NARR). To help understand the physical mechanisms that contribute to changes in the characteristics of daily precipitation, vertically integrated moisture flux convergence (MFC) and precipitable water were included in the study. First, an analysis of the NARR precipitation was carried out because while observed precipitation is indirectly assimilated in the system, differences exist. The NARR mean seasonal amount is very close to that of observations throughout the year, although NARR exhibits a slight systematic bias toward more-frequent, lighter precipitation. Particularly during summer, the precipitation intensity and the probability distribution function (PDF) indicate that NARR somewhat underestimates extremes and overestimates lighter events in the eastern half of the United States. The intensity and PDF of moisture flux convergence exhibit a strong similarity to those of precipitation, suggesting a link between strong MFC and precipitation extremes. On the other hand, the relationship between the precipitable water and precipitation PDFs is weaker, based on the lack of agreement of their gamma distribution parameters. The dependence of the precipitation PDF on the lower-frequency modulation of ENSO was examined. During El Niño winters, the Southwest and central United States, Gulf of Mexico region, and southeastern coast have greater precipitation intensity and extremes than during La Niña, and the Ohio River and Red River basins have lower intensity and fewer extreme events. During summer, the northern Rocky Mountains receive higher intensity precipitation with more extreme events. Most areas where the change in the daily mean precipitation between ENSO phases is large have greater shifts in the extreme tail of the PDF. The ENSO-related response of moisture flux convergence is similar to that of precipitation. ENSO-related shifts in the precipitation PDF do not appear to have a strong relationship to the shifts in precipitable water.

scholarly journals Trends in Wind Speed at Wind Turbine Height of 80 m over the Contiguous United States Using the North American Regional Reanalysis (NARR)

2012 ◽  
Vol 51 (12) ◽  
pp. 2188-2202 ◽  
Author(s):  
Eric Holt ◽  
Jun Wang
Keyword(s):  
United States ◽  
Wind Speed ◽  
Wind Turbine ◽  
Power Law ◽  
North American ◽  
The North ◽  
Spatial Coverage ◽  
Increasing Trend ◽  
North American Regional Reanalysis ◽  
Regional Reanalysis

AbstractThe trends in wind speed at a typical wind turbine hub height (80 m) are analyzed using the North American Regional Reanalysis (NARR) dataset for 1979–2009. A method, assuming the wind profile in the lower boundary layer as power-law functions of altitude, is developed to invert the power exponent (in the power-law equation) from the NARR data and to compute the following variables at 80 m that are needed for the estimation and interpretation of the trend in wind speed: air density, zonal wind u, meridional wind υ, and wind speed. Statistically significant and positive annual trends are found to be predominant over the contiguous United States, with spring and winter being the two largest contributing seasons. Positive trends in surface wind speed are generally smaller than those at 80 m, with less spatial coverage, reflecting stronger increases in wind speed at altitudes above the 80-m level. Large and positive trends in winds over the southeastern region and high-mountain region are primarily due to the increasing trend in southerly wind, while the trends over the northern states (near the Canadian border) are primarily due to the increasing trend in westerly wind. Trends in the 90th percentile of the annual wind speed, a better indicator for the trend in wind power recourses, are 40%–50% larger than but geographically similar to the trends in the annual mean wind speed. The probable climatic drivers for change in wind speed and direction are discussed, and further studies are needed to evaluate the fidelity of wind speed and direction in the NARR.

scholarly journals “The Future of Archaeology Is Antiracist”: Archaeology in the Time of Black Lives Matter

2021 ◽  
pp. 1-20
Author(s):  
Ayana Omilade Flewellen ◽  
Justin P. Dunnavant ◽  
Alicia Odewale ◽  
Alexandra Jones ◽  
Tsione Wolde-Michael ◽  
...  
Keyword(s):  
United States ◽  
North American ◽  
The United States ◽  
Heritage Preservation ◽  
Social Unrest ◽  
Black Lives Matter ◽  
The North ◽  
Road Map ◽  
The Social ◽  
The Future

This forum builds on the discussion stimulated during an online salon in which the authors participated on June 25, 2020, entitled “Archaeology in the Time of Black Lives Matter,” and which was cosponsored by the Society of Black Archaeologists (SBA), the North American Theoretical Archaeology Group (TAG), and the Columbia Center for Archaeology. The online salon reflected on the social unrest that gripped the United States in the spring of 2020, gauged the history and conditions leading up to it, and considered its rippling throughout the disciplines of archaeology and heritage preservation. Within the forum, the authors go beyond reporting the generative conversation that took place in June by presenting a road map for an antiracist archaeology in which antiblackness is dismantled.

scholarly journals Climatology and Meteorological Evolution of Major Wildfire Events over the Northeast United States

2013 ◽  
Vol 28 (1) ◽  
pp. 175-193 ◽  
Author(s):  
Joseph B. Pollina ◽  
Brian A. Colle ◽  
Joseph J. Charney
Keyword(s):  
United States ◽  
Coastal Plain ◽  
Large Scale ◽  
Trajectory Analysis ◽  
Synoptic Pattern ◽  
Pressure System ◽  
Northeast United States ◽  
The North ◽  
North American Regional Reanalysis ◽  
Regional Reanalysis

Abstract This study presents a spatial and temporal climatology of major wildfire events, defined as >100 acres burned (>40.47 ha, where 1 ha = 2.47 acre), in the northeast United States from 1999 to 2009 and the meteorological conditions associated with these events. The northeast United States is divided into two regions: region 1 is centered over the higher terrain of the northeast United States and region 2 is primarily over the coastal plain. About 59% of all wildfire events in these two regions occur in April and May, with ~76% in region 1 and ~53% in region 2. There is large interannual variability in wildfire frequency, with some years having 4–5 times more fire events than other years. The synoptic flow patterns associated with northeast United States wildfires are classified using the North American Regional Reanalysis. The most common synoptic pattern for region 1 is a surface high pressure system centered over the northern Appalachians, which occurred in approximately 46% of all events. For region 2, the prehigh anticyclone type extending from southeast Canada and the Great Lakes to the northeast United States is the most common pattern, occurring in about 46% of all events. A trajectory analysis highlights the influence of large-scale subsidence and decreasing relative humidity during the events, with the prehigh pattern showing the strongest subsidence and downslope drying in the lee of the Appalachians.

A SYNOPSIS OF THE NORTH AMERICAN SPECIES OF SYNDIPNUS (HYMEN., ICHNEUMONIDAE)

1940 ◽  
Vol 72 (7) ◽  
pp. 135-145 ◽  
Author(s):  
G. Stuart Walley
Keyword(s):  
United States ◽  
North American ◽  
The United States ◽  
North American Species ◽  
National Museum ◽  
United States National Museum ◽  
The North

As noted below the two North American species described in Syndipnus by workers appear to belong in other genrra. In Europe the gunus is represented by nearly a score of species and has been reviewed in recent years by two writers (1, 2). North American collections contain very few representatives of the genus; after combining the material in the National Collection with that from the United States National Museum, the latter kindly loaned to me by Mr. R. A. Cushman, only thirty-seven specimens are available for study.

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