scholarly journals An Examination of Precipitation in Observations and Model Forecasts during NAME with Emphasis on the Diurnal Cycle

2007 ◽  
Vol 20 (9) ◽  
pp. 1680-1692 ◽  
Author(s):  
John E. Janowiak ◽  
Valery J. Dagostaro ◽  
Vernon E. Kousky ◽  
Robert J. Joyce
Keyword(s):  
United States ◽  
Diurnal Cycle ◽  
Prediction Models ◽  
Numerical Models ◽  
The United States ◽  
Rain Gauge ◽  
North American Monsoon ◽  
Eastern United States ◽  
Direct Evaluation ◽  
The North

Abstract Summertime rainfall over the United States and Mexico is examined and is compared with forecasts from operational numerical prediction models. In particular, the distribution of rainfall amounts is examined and the diurnal cycle of rainfall is investigated and compared with the model forecasts. This study focuses on a 35-day period (12 July–15 August 2004) that occurred amid the North American Monsoon Experiment (NAME) field campaign. Three-hour precipitation forecasts from the numerical models were validated against satellite-derived estimates of rainfall that were adjusted by daily rain gauge data to remove bias from the remotely sensed estimates. The model forecasts that are evaluated are for the 36–60-h period after the model initial run time so that the effects of updated observational data are reduced substantially and a more direct evaluation of the model precipitation parameterization can be accomplished. The main findings of this study show that the effective spatial resolution of the model-generated precipitation is considerably more coarse than the native model resolution. On a national scale, the models overforecast the frequency of rainfall events in the 1–75 mm day−1 range and underforecast heavy events (>85 mm day−1). The models also have a diurnal cycle that peaks 3–6 h earlier than is observed over portions of the eastern United States and the NAME tier-1 region. Time series and harmonic analysis are used to identify where the models perform well and poorly in characterizing the amplitude and phase of the diurnal cycle of precipitation.

Detections of Directional Dynamic Triggering in Intraplate Regions of the United States

2021 ◽  
Author(s):  
Vivian Tang ◽  
Kevin Chao ◽  
Suzan van der Lee
Keyword(s):  
United States ◽  
Surface Waves ◽  
Seismic Activity ◽  
Active Regions ◽  
The United States ◽  
North American Plate ◽  
Western Boundary ◽  
Eastern United States ◽  
Dynamic Triggering ◽  
The North

ABSTRACT We report tremor or local earthquake signals that occurred during the propagation of Love and Rayleigh waves from the 2012 Mw 8.6 Sumatra earthquake in three intraplate regions: Yellowstone, central Utah, and Raton basin (Colorado). These surface waves likely also dynamically triggered seismic activity along the western boundary of the North American plate, and did not trigger seismic activity in the central and eastern United States. We report additional potential dynamic triggering in the three aforementioned intraplate regions by surface waves from 37 additional large earthquakes, recorded between 2004 and 2017. These surface waves’ transient stresses generally appear to trigger tremor in seismically, volcanically, and hydrothermally active regions, such as Yellowstone, if the waves also arrive from favorable directions. These stresses do not appear to be decisive factors for triggering local earthquakes reported for the Raton basin and central Utah, whereas, surface waves’ incidence angles do appear to be important there.

scholarly journals The recent development of melanism in the larvæ of certain species of Lepidoptera, with an account of its inheritance in Selenia bilunaria esp

1932 ◽  
Vol 111 (770) ◽  
pp. 188-200 ◽  
Keyword(s):  
United States ◽  
Central Europe ◽  
The United States ◽  
Eastern United States ◽  
Evolutionary Processes ◽  
Number Of Species ◽  
The North ◽  
North Eastern ◽  
Geometrid Moth ◽  
State Of Affairs

One of the most remarkable evolutionary processes, the more striking since it has occured before our eyes, has been the rise and spread of melanism and melanochroism amongst the Lepidopetera. Commencing about 1850 in the Manchester area in England with the Geometrid moth Amphidasys betularia L., which yielded the black form carbonaria Jord. ( doubledayaria Mill.), this development has proceeded so rapidly, and become so widespread, that now there is scarcely a country in Northern and Central Europe which does not produce its quota of melanic insects. Moreover, the same state of affairs exists in the North-Eastern United States, although there the number of species affected, up to the present, is not so great as in Europe. Another important feature about these changes lies in the circumstance that, almost uniformly, in Europe and in the United States, the first species to exhibit melanism in any given area have been Amphidasys betularia and Tephrosia crepuscularia . From the beginning, the Geometridæ, more especially the subfamily Boarmiinæ, have provided not only the bulk of the melanic varieties, but also the greatest numbers of individuals. In many areas, as for example in the case of A. betularia and Y psipetes trifasciata , only black examples occur. Nevertheless, other groups include species which have gone black; for instance, the Noctuidæ present black forms of Aplecta nebulosa Hufn., the Cymatophoridæ of Cymatophora or F., the Arctiidæ of Spilosoma lubricipeda L., the Gelechiidæ of Chimabacche fagella F., and so on.

Applications of Monsoon Research: Opportunities to Inform Decision Making and Reduce Regional Vulnerability

2007 ◽  
Vol 20 (9) ◽  
pp. 1608-1627 ◽  
Author(s):  
Andrea J. Ray ◽  
Gregg M. Garfin ◽  
Margaret Wilder ◽  
Marcela Vásquez-León ◽  
Melanie Lenart ◽  
...  
Keyword(s):  
United States ◽  
Decision Making ◽  
North American ◽  
Knowledge Exchange ◽  
The United States ◽  
North American Monsoon ◽  
Precipitation Regime ◽  
The North ◽  
Integrated Assessments ◽  
Inform Decision Making

Abstract This article presents ongoing efforts to understand interactions between the North American monsoon and society in order to develop applications for monsoon research in a highly complex, multicultural, and binational region. The North American monsoon is an annual precipitation regime that begins in early June in Mexico and progresses northward to the southwestern United States. The region includes stakeholders in large urban complexes, productive agricultural areas, and sparsely populated arid and semiarid ecosystems. The political, cultural, and socioeconomic divisions between the United States and Mexico create a broad range of sensitivities to climate variability as well as capacities to use forecasts and other information to cope with climate. This paper highlights methodologies to link climate science with society and to analyze opportunities for monsoon science to benefit society in four sectors: natural hazards management, agriculture, public health, and water management. A list of stakeholder needs and a calendar of decisions is synthesized to help scientists link user needs to potential forecasts and products. To ensure usability of forecasts and other research products, iterative scientist–stakeholder interactions, through integrated assessments, are recommended. These knowledge-exchange interactions can improve the capacity for stakeholders to use forecasts thoughtfully and inform the development of research, and for the research community to obtain feedback on climate-related products and receive insights to guide research direction. It is expected that integrated assessments can capitalize on the opportunities for monsoon science to inform decision making and, in the best instances, reduce regional climate vulnerabilities and enhance regional sustainability.

scholarly journals A Precipitation Climatology and Dataset Intercomparison for the Western United States

2008 ◽  
Vol 9 (5) ◽  
pp. 825-841 ◽  
Author(s):  
Kristen J. Guirguis ◽  
Roni Avissar
Keyword(s):  
United States ◽  
Principal Component ◽  
Cold Season ◽  
Rain Gauge ◽  
Department Of Energy ◽  
Western United States ◽  
North American Monsoon ◽  
Precipitation Climatology ◽  
The North ◽  
Data Products

Abstract This paper presents the results of a regionalization study of the precipitation climate of the western United States using principal component analysis. Past eigen-based regionalization studies have relied on rain gauge networks, which is restrictive because rain gauge coverage is sparse, especially over complex terrain that exists in the western United States. Here, the use of alternate data products is examined by conducting a comparative regionalization using nine precipitation datasets used in hydrometeorological research. Five unique precipitation climates are identified within the western United States, which have centers and boundaries that are physically reasonable and that highlight the relationship between the precipitation climatology and local topography. Using the congruence coefficient as the measure of similarity between principal component solutions, the method is found to be generally stable across datasets. The exception is the National Centers for Environmental Prediction–Department of Energy (NCEP–DOE) Reanalysis 2, which frequently demonstrates only borderline agreement with the other datasets. The loading pattern differences among datasets are shown to be primarily a result of data differences in the representation of (i) precipitation over the Rocky Mountains, (ii) the eastward wet-to-dry precipitation gradient that occurs during the cold season, (iii) the magnitude and spatial extent of the North American monsoon signal, and (iv) precipitation in the desert southwest during spring and summer. Sensitivity tests were conducted to determine whether the spatial resolution and temporal domain of the input data would dramatically affect the solution, and these results show the methodology to be stable to differences in spatial/temporal data features. The results suggest that alternate data products can be used in regionalization studies, which has applications for rain gauge installation and planning, climate research, and numerical modeling experiments.

Synthesis of Results from the North American Monsoon Experiment (NAME) Process Study

2007 ◽  
Vol 20 (9) ◽  
pp. 1601-1607 ◽  
Author(s):  
Wayne Higgins ◽  
David Gochis
Keyword(s):  
United States ◽  
Central America ◽  
North American ◽  
The United States ◽  
Background Information ◽  
North American Monsoon ◽  
The North ◽  
Process Study ◽  
Monsoon System ◽  
United States Mexico

Abstract An international team of scientists from the United States, Mexico, and Central America carried out a major field campaign during the summer of 2004 to develop an improved understanding of the North American monsoon system leading to improved precipitation forecasts. Results from this campaign, which is the centerpiece of the North American Monsoon Experiment (NAME) Process Study, are reported in this issue of the Journal of Climate. In addition to a synthesis of key findings, this brief overview article also raises some important unresolved issues that require further attention. More detailed background information on NAME, including motivating science questions, where NAME 2004 was conducted, when, and the experimental design, was published previously by Higgins et al.

scholarly journals Simulation of the North American Monsoon by the NCAR CCM3 and Its Sensitivity to Convection Parameterization

2006 ◽  
Vol 19 (12) ◽  
pp. 2851-2866 ◽  
Author(s):  
J. Craig Collier ◽  
Guang J. Zhang
Keyword(s):  
Relative Humidity ◽  
Diurnal Cycle ◽  
North American ◽  
Large Scale ◽  
The United States ◽  
Experimental Simulation ◽  
Specific Humidity ◽  
North American Monsoon ◽  
Hourly Precipitation ◽  
The North

Abstract Two 9-yr runs of the NCAR Community Climate Model version 3 (CCM3) are compared in their simulations of the North American summer monsoon. In a control simulation, the Zhang–McFarlane deep convection scheme is used. For an experimental simulation, the following modifications to the scheme are implemented. The closure is based on the large-scale forcing of virtual temperature, and a relative humidity threshold on convective parcels lifted from the boundary layer is applied. The sensitivity to these modifications for simulating the North American monsoon is investigated. Model validation relies on hourly precipitation rates from surface gauges over the United States, hourly precipitation rates derived from the combination of microwave and radar measurements from NASA’s Tropical Rainfall Measuring Mission (TRMM) satellite over Mexico, and CAPE values as calculated from temperature, specific humidity, and pressure fields from the NCEP–NCAR reanalysis. Results show that the experimental run improves the timing of the monsoon onset and peak in the regions of core monsoon influence considered here, though it increases a negative bias in the peak monsoon intensity in one region of northern Mexico. Sensitivity of the diurnal cycle of precipitation to modifications in the convective scheme is highly geographically dependent. Using a combination of gauge-based rainfall rates and reanalysis-based CAPE, it is found that improvements in the simulated diurnal cycle are confined to a convective regime in which the diurnal evolution of precipitation is observed to lag that of CAPE. For another regime, in which CAPE is observed to be approximately in phase with precipitation, model phase biases increase nearly everywhere. Some of the increased phase biases in the latter regime are primarily because of application of the relative humidity threshold.

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 A Multiplatform-Merged (MPM) SST Analysis

2007 ◽  
Vol 20 (9) ◽  
pp. 1662-1679 ◽  
Author(s):  
Wanqiu Wang ◽  
Pingping Xie
Keyword(s):  
Gulf Of California ◽  
Numerical Models ◽  
Tropical Rainfall Measuring Mission ◽  
The United States ◽  
Western Hemisphere ◽  
North American Monsoon ◽  
Small Scale ◽  
Tropical Instability Waves ◽  
The North ◽  
Microwave Imager

Abstract Previous observational studies indicated that local sea surface temperatures (SSTs) near the west coast of the United States, in the Gulf of California, and in the Gulf of Mexico have strong impacts on the North American monsoon (NAM) system. Simulations of the NAM by numerical models are also found to be sensitive to the specification of SSTs. Accordingly, a reliable SST dataset is essential for improving the understanding, simulation, and prediction of the NAM system. In this study, a new fine-resolution SST analysis is constructed by merging in situ observations from ships and buoys with retrievals from National Oceanic and Atmospheric Administration (NOAA) satellites (NOAA-16 and NOAA-17), Geostationary Operational Environmental Satellites (GOES), the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI), and the Advanced Microwave Scanning Radiometer (AMSR). Called the multiplatform-merged (MPM) SST analysis, this new product of 3-hourly SST is defined on a 0.25° × 0.25° latitude–longitude grid over the Western Hemisphere (30°S–60°N, 180°–30°W). The analysis for the period of 15 May–30 September 2004 shows that the MPM is capable of capturing small-scale disturbances such as those associated with the tropical instability waves. It also depicts local sharp gradients around Baja California and the Gulf Stream with reasonable accuracy compared with the existing analyses. Experiments have been conducted to examine the impacts of the addition of satellite observations on the quality of the MPM analysis. Results showed that inclusion of observations from more satellites progressively improves the quantitative accuracy, especially for diurnal amplitude of the analysis, indicating the importance of accommodating observations from multiple platforms in depicting critical details in an SST analysis with high temporal and spatial resolutions.

scholarly journals Enhanced Stratospheric Water Vapor over the Summertime Continental United States and the Role of Overshooting Convection

2016 ◽  
Author(s):  
Robert L. Herman ◽  
Eric A. Ray ◽  
Karen H. Rosenlof ◽  
Kristopher M. Bedka ◽  
Michael J. Schwartz ◽  
...  
Keyword(s):  
United States ◽  
Water Vapor ◽  
The United States ◽  
Atmospheric Composition ◽  
North American Monsoon ◽  
Back Trajectory ◽  
Stratospheric Water Vapor ◽  
Mixing Ratios ◽  
The North ◽  
Back Trajectory Analysis

Abstract. The NASA ER-2 aircraft sampled the UTLS region over North America during the NASA Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) field mission. This study reports three case studies of convectively-influenced air parcels with enhanced water vapor in the overworld stratosphere over the summertime continental United States. Water vapor mixing ratios greater than 10 ppmv, more than twice the stratospheric background levels, were measured by the JPL Laser Hygrometer (JLH Mark2) at pressure levels between 80 and 160 hPa. Through satellite observations and analysis, we make the connection between these in situ water measurements and overshooting cloud tops. The overshooting tops (OT) are identified from a SEAC4RS OT detection product based on satellite infrared window channel brightness temperature gradients. Back trajectory analysis ties enhanced water to OT one to seven days prior to the intercept by the aircraft. The trajectory paths are dominated by the North American Monsoon (NAM) anticyclonic circulation. This connection suggests that ice is convectively transported to the overworld stratosphere in OT events and subsequently sublimated; such events may irreversibly enhance stratospheric water vapor in the summer over Mexico and the United States. Regional context is provided by water observations from the Aura Microwave Limb Sounder (MLS).

scholarly journals The experience of guestworkers at a United States tourist resort

2013 ◽  
Vol 10 (2) ◽  
pp. 198-228
Author(s):  
Guilherme Mansur Dias
Keyword(s):  
United States ◽  
The United States ◽  
Temporary Employment ◽  
Eastern United States ◽  
Labour Relations ◽  
The North ◽  
North Eastern ◽  
The Us ◽  
Ethnographic Analysis

This article examines temporary employment among foreign workers at the Okemo Mountain Resort, a tourist ski complex located in Vermont state in the north-eastern United States. I discuss the meanings associated with the international displacement of these workers, focusing especially on the ideas and imagery surrounding 'mobility', 'work,' 'travel' and 'youth.' By describing their experiences, along with the practices and discourses of the employer and the US State, the case study shows how Okemo's strategy of hiring a flexible foreign workforce is connected to the multiple meanings through which these groups represent their experience of temporary migration to the United States in the context of increasingly precarious labour relations. The ethnographic analysis proposed by the research provides a counterpoint to the 'macro-analytical' approach employed by most studies on the issue of foreign temporary work in the United States.

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