Comparison of Ground-Based Radar and Geosynchronous Satellite Climatologies of Warm-Season Precipitation over the United States

2008 ◽  
Vol 47 (12) ◽  
pp. 3264-3270 ◽  
Author(s):  
John D. Tuttle ◽  
Richard E. Carbone ◽  
Phillip A. Arkin
Keyword(s):  
United States ◽  
Brightness Temperature ◽  
Satellite Data ◽  
Warm Season ◽  
Propagation Speed ◽  
Radar Data ◽  
The United States ◽  
Temperature Threshold ◽  
Brightness Temperatures ◽  
The Difference

Abstract Studies in the past several years have documented the climatology of warm-season precipitation-episode statistics (propagation speed, span, and duration) over the United States using a national composited radar dataset. These climatological studies have recently been extended to other continents, including Asia, Africa, and Australia. However, continental regions outside the United States have insufficient radar coverage, and the newer studies have had to rely on geostationary satellite data at infrared (IR) frequencies as a proxy for rainfall. It is well known that the use of IR brightness temperatures to infer rainfall is subject to large errors. In this study, the statistics of warm-season precipitation episodes derived from radar and satellite IR measurements over the United States are compared and biases introduced by the satellite data are evaluated. It is found that the satellite span and duration statistics are highly dependent upon the brightness temperature threshold used but with the appropriate choices of thresholds can be brought into good agreement with those based upon radar data. The propagation-speed statistics of satellite events are on average ∼4 m s−1 faster than radar events and are relatively insensitive to the brightness temperature threshold. A simple correction procedure based upon the difference between the steering winds for the precipitation core and the winds at the level of maximum anvil outflow is developed.

scholarly journals Climatology of Linear Mesoscale Convective System Morphology in the United States based on Random Forests Method

2021 ◽  
pp. 1-52
Author(s):  
Wenjun Cui ◽  
Xiquan Dong ◽  
Baike Xi ◽  
Zhe Feng
Keyword(s):  
United States ◽  
Great Plains ◽  
Warm Season ◽  
Mesoscale Convective System ◽  
Propagation Speed ◽  
Extreme Rainfall ◽  
The United States ◽  
Convective System ◽  
Large Variability ◽  
Mesoscale Convective

AbstractThis study uses machine learning methods, specifically the random forest (RF), on a radar-based mesoscale convective system (MCS) tracking dataset to classify the five types of linear MCS morphology in the contiguous United States during the period 2004-2016. The algorithm is trained using radar- and satellite-derived spatial and morphological parameters, and reanalysis environmental information from 5-yr manually identified nonlinear and five linear MCS modes. The algorithm is then used to automate the classification of linear MCSs over 8 years with high accuracy, providing a systematic, long-term climatology of linear MCSs. Results reveal that nearly 40% of MCSs are classified as linear MCSs, in which half of the linear events belong to the type of system having a leading convective line. The occurrence of linear MCSs shows large annual and seasonal variations. On average, 113 linear MCSs occur annually during the warm season (through March to October), with most of these events clustered from May through August in the central eastern Great Plains. MCS characteristics, including duration, propagation speed, orientation, and system cloud size, have large variability among the different linear modes. The systems having a trailing convective line and the systems having a back-building area of convection typically move more slowly and have higher precipitation rate, and thus have higher potential in producing extreme rainfall and flash flooding. Analysis of the environmental conditions associated with linear MCSs show that the storm-relative flow is of most importance in determining the organization mode of linear MCSs.

scholarly journals The Effect of Massachusetts' Health Reform on Employer-Sponsored Insurance Premiums

2010 ◽  
Vol 13 (2) ◽  
Author(s):  
John F Cogan ◽  
R. Glenn Hubbard ◽  
Daniel Kessler
Keyword(s):  
United States ◽  
Health Reform ◽  
Medical Expenditure Panel Survey ◽  
Private Insurance ◽  
The United States ◽  
Medical Expenditure ◽  
Insurance Premiums ◽  
Reform Plan ◽  
The Difference ◽  
The Cost

In this paper, we use publicly available data from the Medical Expenditure Panel Survey - Insurance Component (MEPS-IC) to investigate the effect of Massachusetts' health reform plan on employer-sponsored insurance premiums. We tabulate premium growth for private-sector employers in Massachusetts and the United States as a whole for 2004 - 2008. We estimate the effect of the plan as the difference in premium growth between Massachusetts and the United States between 2006 and 2008—that is, before versus after the plan—over and above the difference in premium growth for 2004 to 2006. We find that health reform in Massachusetts increased single-coverage employer-sponsored insurance premiums by about 6 percent, or $262. Although our research design has important limitations, it does suggest that policy makers should be concerned about the consequences of health reform for the cost of private insurance.

scholarly journals La contrebande des produits du tabac au Canada entre 1985 et 1994 et le cas particulier du Québec

Criminologie ◽  
2005 ◽  
Vol 30 (1) ◽  
pp. 53-72 ◽  
Author(s):  
Marc Alain
Keyword(s):  
United States ◽  
Driving Force ◽  
The United States ◽  
Eastern Canada ◽  
Mass Consumption ◽  
Cigarette Taxes ◽  
Geographical Factors ◽  
The World ◽  
The Difference

The professional smuggling of mass consumption products develops when demand for a product is not adequately fulfilled by the legitimate market. The difficulties encountered in supplying are, in most contemporary cases, caused by real rarity of the desired product. For other cases, however, the rarity is largely virtual in that government taxes aimed at the product in question lead to increasing the product's price to a prohibitive end. This was the case with cigarettes in Canada between 1985 and 1994. Before both, the federal and provincial, governments decided to drastically decrease cigarette taxes in February 1994, the price for a pack of cigarettes was five to six times higher than the same product in the United States. This article begins with a brief review of the contribution made by economists in regard to contemporary smuggling. Focus will be aimed at common characteristics of the smuggling phenomenon across the world. Elements which are more particular to the Canadian smuggling situation will be identified as well. While the difference in the price of cigarettes between Canada and the United States would seem to be the undeniable driving force behind the development of smuggling activities at the countries ' border, one key question remains unexplained. Why was the volume of contraband unequally distributed across Canada even though the price of cigarettes remained largely consistent throughout all provinces? The level of organization of smuggling networks was much higher in Eastern Canada, and particularly in Quebec, than it was in the western provinces. It is argued that the reasons for this are not only due to price, but to a series of political, historical, and geographical factors which allowed cigarette smugglers to function better in Quebec than in the rest of the country.

Equal Opportunity in a Pluralistic Society

1987 ◽  
Vol 5 (1) ◽  
pp. 104-119 ◽  
Author(s):  
James W. Nickel
Keyword(s):  
United States ◽  
Religious Pluralism ◽  
Equal Opportunity ◽  
Religious Diversity ◽  
The United States ◽  
Pluralistic Society ◽  
Self Image ◽  
The Difference ◽  
The U.S

The United States has never been culturally or religiously homogeneous, but its diversity has greatly increased over the last century. Although the U.S. was first a multicultural nation through conquest and enslavement, its present diversity is due equally to immigration. In this paper I try to explain the difference it makes for one area of thought and policy – equal opportunity – if we incorporate cultural and religious pluralism into our national self-image. Formulating and implementing a policy of equal opportunity is more difficult in diverse, pluralistic countries than it is in homogeneous ones. My focus is cultural and religious diversity in the United States, but my conclusions will apply to many other countries – including ones whose pluralism is found more in religion than in culture.

scholarly journals An analysis of income differentials by marital status

2008 ◽  
Vol 38 (2) ◽  
pp. 267-292 ◽  
Author(s):  
Regina Madalozzo
Keyword(s):  
United States ◽  
Marital Status ◽  
The United States ◽  
Married Women ◽  
Empirical Literature ◽  
Income Differentials ◽  
Marriage Premium ◽  
Unmarried Cohabitation ◽  
Marriage Penalty ◽  
The Difference

Unmarried cohabitation has become a more frequently observed phenomenon over the last three decades, and not only in the United States. The objective of this work is to examine income differentials between married women and those who remain single or cohabitate. The empirical literature shows that, while the marriage premium is verified in different studies for men, the result for women is not conclusive. The main innovation of my study is the existence of controls for selection. In this study, we have two sources of selectivity: into the labor force and into a marital status category. The switching regressions and the Oaxaca decomposition results demonstrate the existence of a significant penalty for marriage. Correcting for both types of selection, the difference in wages varies between 49% and 53%, when married women are compared with cohabiting ones, and favors non-married women. This result points to the existence of a marriage penalty.

scholarly journals INTERVENSI KEBIJAKAN MONETER TERHADAP INVESTASI PORTOFOLIO: KASUS INDONESIA DAN AMERIKA SERIKAT

2020 ◽  
Vol 2 (1) ◽  
pp. 1
Author(s):  
Nanda Alfarina ◽  
Hasdi Aimon
Keyword(s):  
United States ◽  
Interest Rate ◽  
Secondary Data ◽  
The United States ◽  
Portfolio Investment ◽  
Mechanism Analysis ◽  
Long Run ◽  
Negative Effect ◽  
The Difference ◽  
Effect Of Monetary Policy

This study aims to determine the effect of monetary policy measured by the central bank’s policy rate (X1) on portfolio investment (Y) in Indonesia and United States in the long run. The data used are secondary data seouced from SEKI BI, FRED The FEd, coinmarketcap.com, and investing.com, with the VECM (Vector Error Correction Mechanism) analysis methode. The study show The study shows the differences between the results that occur in Indonesia and the United States. The policy interest rate has a significant positive effect on portfolio investment in the long run in Indonesia, while in the United States the interest rate in the long run has a significant negative effect on portfolio investment. The difference in research results between the two countries shows the need for different treatment for monetary authorities in encouraging portfolio investment 

scholarly journals Book Review | George Will’s Conservatism and Democracy in Crisis

2020 ◽  
Vol 9 (2) ◽  
Keyword(s):  
United States ◽  
Direct Democracy ◽  
The United States ◽  
James Madison ◽  
American Government ◽  
Federalist Papers ◽  
The Federalist ◽  
The Difference ◽  
The Government ◽  
The Federalist Papers

Americans typically view the United States as a democracy and are rightly proud of that. Of course, as those of a more precise nature, along with smug college students enrolled in introductory American government classes, are quick to point out, the United States is technically a republic. This is a bit too clever by half since James Madison, in The Federalist Papers, defined a republic the way most people think of a democracy—a system of representative government with elections: “[The]… difference between a Democracy and a Republic are, first the delegation of the Government, in the latter, to a small number of citizens elected by the rest.” What the framers thought of as democracy is today referred to as direct democracy, the belief that citizens should have more direct control over governing. The Athenian assembly was what the framers, Madison in particular, saw as the paragon of direct democracy—and as quite dangerous. While direct democracy has its champions, most Americans equate democracy with electing officials to do the business of government.

scholarly journals A 5-yr 40-km-Resolution Global Climatology of Superrefraction for Ground-Based Weather Radars

2009 ◽  
Vol 48 (1) ◽  
pp. 89-110 ◽  
Author(s):  
Philippe Lopez
Keyword(s):  
United States ◽  
Electromagnetic Waves ◽  
Vertical Gradient ◽  
Radar Data ◽  
The United States ◽  
Horizontal Resolution ◽  
Trade Wind ◽  
Late Afternoon ◽  
The Balkans ◽  
Radar Images

Abstract The propagation of electromagnetic waves emitted from ground-based meteorological radars is determined by the stratification of the atmosphere. In extreme superrefractive situations characterized by strong temperature inversions or strong vertical gradients of moisture, the radar beam can be deflected toward the ground (ducting or trapping). This phenomenon often results in spurious returned echoes and misinterpretation of radar images such as erroneous precipitation detection. In this work, a 5-yr global climatology of the frequency of superrefractive and ducting conditions and of trapping-layer base height has been produced using refractivity computations from ECMWF temperature, moisture, and pressure analyses at a 40-km horizontal resolution. The aim of this climatology is to better document how frequent such events are, which is a prerequisite for fully benefiting from radar data information for the multiple purposes of model validation, precipitation analysis, and data assimilation. First, the main climatological features are summarized for the whole globe: high- and midlatitude oceans seldom experience superrefraction or ducting whereas tropical oceans are strongly affected, especially in regions where the trade wind inversion is intense and lying near the surface. Over land, seasonal averages of superrefraction (ducting) frequencies reach 80% (40%) over tropical moist areas year-round but remain below 40% (15%) in most other regions. A particular focus is then laid on Europe and the United States, where extensive precipitation radar networks already exist. Seasonal statistics exhibit a pronounced diurnal cycle of ducting occurrences, with averaged frequencies peaking at 60% in summer late afternoon over the eastern half of the United States, the Balkans, and the Po Valley but no ducts by midday. Similarly high ducting frequencies are found over the southwestern coast of the United States at night. A potentially strong reduction of ducting occurrences with increased radar height (especially in midlatitude summer late afternoon) is evidenced by initiating refractivity vertical gradient computations from either the lowest or the second lowest model level. However, installing radar on tall towers also brings other problems, such as a possible amplification of sidelobe clutter echoes.

scholarly journals Variability of Warm-Season Cloud Episodes over East Asia Based on GMS Infrared Brightness Temperature Observations

2005 ◽  
Vol 133 (6) ◽  
pp. 1478-1500 ◽  
Author(s):  
Chung-Chieh Wang ◽  
George Tai-Jen Chen ◽  
Richard E. Carbone
Keyword(s):  
East Asia ◽  
Brightness Temperature ◽  
Intraseasonal Variability ◽  
Warm Season ◽  
Propagation Speed ◽  
Regional Variability ◽  
Mountain Areas ◽  
Time Space ◽  
Geostationary Meteorological Satellite ◽  
Temperature Observations

Abstract The present study has used the Geostationary Meteorological Satellite (GMS) IR brightness temperature observations to investigate the regional and intraseasonal variability of east Asian warm-season cloud/precipitation episodes (in distance–time space) due to land–sea contrast and latitudinal effects. The data period was May–August 1998–2001, and harmonic analysis was employed as the major tool for analysis. The full domain of study (20°–40°N, 95°–145°E) was divided into northern and southern zones, and into eastern and western sectors, and statistics of episodes in each subregion were derived and compared. For latitudinal effects, episodes were found to be significantly larger in span and duration in northern (30°–40°N) than in southern (20°–30°N) zones. In the northern zone, the propagation characteristics were also stronger and remain evident even in midsummer, while episodes south of 30°N reversed in direction and traveled westward in July and August. For land–sea contrast, the May–August transition over land (western sector, 95°–120°E) was mainly characterized by an increase in diurnal activities, while that over ocean (eastern sector, 120°–145°E) was characterized by decreased overall activities instead. Over the land itself, significant regional variability also existed, with strongest diurnal signals over the eastern Tibetan Plateau near 100°E, and increased diurnal activities over mountain areas in southeastern China since June. Between the two bands, near 107°E, semidiurnal signals were relatively strong and became dominant in June. This double-peaked structure in the diurnal cycle resulted from overlying signals of convection propagating eastward off the plateau with those induced locally in late afternoon, and the phenomenon was more evident in May–June. Over the ocean, on the other hand, both diurnal and semidiurnal waves had small amplitudes, and the regional variability was much weaker. For intraseasonal transition, the number of large episodes was reduced from May through July, as was mean propagation speed. In August, however, some larger events started to reappear over east Asia.

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