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 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.

scholarly journals El mayor registro de elevación de Mustela frenata (Carnivora: Mustelidae) y distribución en el departamento de Calda, región andina de Colombia

2014 ◽  
Vol 1 (2) ◽  
pp. 7-9
Author(s):  
Sergio Escobar-Lasso ◽  
Margarita Gil-Fernández
Keyword(s):  
United States ◽  
South America ◽  
Sea Level ◽  
The United States ◽  
Western Hemisphere ◽  
Geographical Range ◽  
The North ◽  
Northern South America

The long-tailed weasel Mustela frenata Lichtenstein, 1831 has the greatest geographical range among mustelids in the western hemisphere (Harding & Dragoo 2012). The range of M. frenata extends from the north of the United States, near the Canadian border, to northern South America (Sheffield & Thomas 1997), from sea level to 3800 masl (Sheffield & Thomas 1997, Reid & Helgen 2008).

scholarly journals A Numerical Investigation of Wet and Dry Onset Modes in the North American Monsoon Core Region. Part I: A Regional Mechanism for Interannual Variability

2012 ◽  
Vol 25 (11) ◽  
pp. 3953-3969 ◽  
Author(s):  
Cuauhtémoc Turrent ◽  
Tereza Cavazos
Keyword(s):  
Interannual Variability ◽  
Diurnal Cycle ◽  
North American ◽  
Gulf Of California ◽  
Deep Convection ◽  
Core Region ◽  
Eastern Pacific ◽  
North American Monsoon ◽  
The Core ◽  
The North

In this study the results of two regional fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5) simulations forced at their boundaries with low-pass-filtered North American Regional Reanalysis (NARR) composite fields from which synoptic-scale variability was removed are presented. The filtered NARR data are also assimilated into the inner domain through the use of field nudging. The purpose of this research is to investigate wet and dry onset modes in the core region of the North American monsoon (NAM). Key features of the NAM that are present in the NARR fields and assimilated into the regional simulations include the position of the midlevel anticyclone, low-level circulation over the Gulf of California, and moisture flux patterns into the core monsoon region, for which the eastern Pacific is the likely primary source of moisture. The model develops a robust diurnal cycle of deep convection over the peaks of the Sierra Madre Occidental (SMO) that results solely from its radiation scheme and internal dynamics, in spite of the field nudging. The wet onset mode is related to a regional land–sea thermal contrast (LSTC) that is ~2°C higher than in the dry mode, and is further characterized by a northward-displaced midlevel anticyclone, a stronger surface pressure gradient along the Gulf of California, larger mean moisture fluxes into the core region from the eastern Pacific, a stronger diurnal cycle of deep convection, and the more northward distribution of precipitation along the axis of the SMO. A proposed regional LSTC mechanism for NAM onset interannual variability is consistent with the differences between both onset modes.

scholarly journals Tropical and Extratropical Controls of Gulf of California Surges and Summertime Precipitation over the Southwestern United States

2016 ◽  
Vol 144 (7) ◽  
pp. 2695-2718 ◽  
Author(s):  
Salvatore Pascale ◽  
Simona Bordoni
Keyword(s):  
Time Scales ◽  
Gulf Of California ◽  
Dominant Role ◽  
Principal Component ◽  
North American Monsoon ◽  
Atmospheric Variability ◽  
Near Surface ◽  
The North ◽  
Precipitation Anomalies ◽  
The Relationship

Abstract In this study ERA-Interim data are used to study the influence of Gulf of California (GoC) moisture surges on the North American monsoon (NAM) precipitation over Arizona and western New Mexico (AZWNM), as well as the connection with larger-scale tropical and extratropical variability. To identify GoC surges, an improved index based on principal component analyses of the near-surface GoC winds is introduced. It is found that GoC surges explain up to 70% of the summertime rainfall over AZWNM. The number of surges that lead to enhanced rainfall in this region varies from 4 to 18 per year and is positively correlated with annual summertime precipitation. Regression analyses are performed to explore the relationship between GoC surges, AZWNM precipitation, and tropical and extratropical atmospheric variability at the synoptic (2–8 days), quasi-biweekly (10–20 days), and subseasonal (25–90 days) time scales. It is found that tropical and extratropical waves, responsible for intrusions of moist tropical air into midlatitudes, interact on all three time scales, with direct impacts on the development of GoC surges and positive precipitation anomalies over AZWNM. Strong precipitation events in this region are, however, found to be associated with time scales longer than synoptic, with the quasi-biweekly and subseasonal modes playing a dominant role in the occurrence of these more extreme events.

scholarly journals Relating Passive 37-GHz Scattering to Radar Profiles in Strong Convection

2011 ◽  
Vol 50 (1) ◽  
pp. 233-240 ◽  
Author(s):  
Daniel J. Cecil
Keyword(s):  
Central Africa ◽  
Tropical Rainfall Measuring Mission ◽  
The United States ◽  
Phase Layer ◽  
Tropical Ocean ◽  
Convective Systems ◽  
Freezing Level ◽  
Brightness Temperatures ◽  
Microwave Imager ◽  
Ice Water

Abstract Tropical Rainfall Measuring Mission (TRMM) Microwave Imager and precipitation radar measurements are examined for strong convective systems. Storms having similar values of minimum 37-GHz polarization-corrected temperature (PCT) are grouped together, and their vertical profiles of maximum radar reflectivity are composited. Lower 37-GHz PCT corresponds to stronger radar profiles (high reflectivity through a deep layer), but characteristic profiles for a given 37-GHz PCT are different for deep tropical ocean, deep tropical land, subtropical ocean, and subtropical land regions. Tropical oceanic storms have a sharper decrease of reflectivity just above the freezing level than storms from other regions with the same brightness temperature. Storms from subtropical land regions have the slowest decrease of reflectivity with height and the greatest mixed-phase-layer ice water content (IWC). Linear fits of 37-GHz PCT versus IWC for each region are used to scale the brightness temperatures. Counts of storms with these scaled brightness temperatures below certain thresholds suggest that not as many of the strongest storms occur in central Africa as in subtropical parts of South America, the United States, and central Asia.

scholarly journals Multiscale Variability of the Flow during the North American Monsoon Experiment

2007 ◽  
Vol 20 (9) ◽  
pp. 1628-1648 ◽  
Author(s):  
Richard H. Johnson ◽  
Paul E. Ciesielski ◽  
Brian D. McNoldy ◽  
Peter J. Rogers ◽  
Richard K. Taft
Keyword(s):  
United States ◽  
North American ◽  
Gulf Of California ◽  
Large Scale ◽  
Regional Scale ◽  
North American Monsoon ◽  
Return Flow ◽  
Southwestern United States ◽  
The North ◽  
Upper Level

Abstract The 2004 North American Monsoon Experiment (NAME) provided an unprecedented observing network for studying the structure and evolution of the North American monsoon. This paper focuses on multiscale characteristics of the flow during NAME from the large scale to the mesoscale using atmospheric sounding data from the enhanced observing network. The onset of the 2004 summer monsoon over the NAME region accompanied the typical northward shift of the upper-level anticyclone or monsoon high over northern Mexico into the southwestern United States, but in 2004 this shift occurred slightly later than normal and the monsoon high did not extend as far north as usual. Consequently, precipitation over the southwestern United States was slightly below normal, although increased troughiness over the Great Plains contributed to increased rainfall over eastern New Mexico and western Texas. The first major pulse of moisture into the Southwest occurred around 13 July in association with a strong Gulf of California surge. This surge was linked to the westward passages of Tropical Storm Blas to the south and an upper-level inverted trough over northern Texas. The development of Blas appeared to be favored as an easterly wave moved into the eastern Pacific during the active phase of a Madden–Julian oscillation. On the regional scale, sounding data reveal a prominent sea breeze along the east shore of the Gulf of California, with a deep return flow as a consequence of the elevated Sierra Madre Occidental (SMO) immediately to the east. Subsidence produced a dry layer over the gulf, whereas a deep moist layer existed over the west slopes of the SMO. A prominent nocturnal low-level jet was present on most days over the northern gulf. The diurnal cycle of heating and moistening (Q1 and Q2) over the SMO was characterized by deep convective profiles in the mid- to upper troposphere at 1800 LT, followed by stratiform-like profiles at midnight, consistent with the observed diurnal evolution of precipitation over this coastal mountainous region. The analyses in the core NAME domain are based on a gridded dataset derived from atmospheric soundings only and, therefore, should prove useful in validating reanalyses and regional models.

Indigenous Food Systems: Battling Whiteness through Decolonization

1969 ◽  
Author(s):  
Katie King
Keyword(s):  
Food Systems ◽  
Community Gardens ◽  
The United States ◽  
Alternative Food ◽  
Farmers Markets ◽  
Alternative Food Networks ◽  
Small Scale ◽  
Alternative Food Systems ◽  
Post Colonial ◽  
The North

Shaw (2006) argues that “the rubrics of difference against which Whiteness is commonly juxtaposed rarely includes Indigeneity, or the experiences of Indigenous peoples regardless of the North American domination of the field, and its settler context” (853). Viewing Canada and the United States as post-colonial nations, this paper seeks to broaden understandings of Indigenous food production, distribution, and consumption practices and/or projects and how they work to resist colonial histories of oppression. hooks (1992) defines decolonization as “a process of cultural and historical liberation; an act of confrontation with a dominant system of thought” (1). Using the concept of “Whiteness”, this research attempts to prove how small-scale Indigenous food systems located in North America decolonize dominant ways of seeing alternative food systems as white food spaces. To present this research to an interdisciplinary audience I will first attend to defining key concepts informing this research including: post-colonial nation, decolonization, Whiteness, and Indigeneity. I will then spend some time exploring what Sarah Whatmore describes as “Alternative Food Networks” (AFNs) and claims as “white food spaces”. Finally, in an attempt to decolonize alternative food systems as white spaces, I will share various forms of present-day, small-scale Indigenous food systems such as Wild Rice production by The White Earth Anishinaabe, the ‘Food from the Land’ program in the O-pipon-Na-Piwin Cree Nation, and various Indigenous farmers markets and community gardens.  

Relationship between Boreal Summer Circulation Trend and Destructive Stationary-Transient Wave Interference in the Western Hemisphere

2021 ◽  
pp. 1-38
Author(s):  
Dong Wan Kim ◽  
Sukyoung Lee
Keyword(s):  
Interference Pattern ◽  
Western Hemisphere ◽  
Boreal Summer ◽  
North American Monsoon ◽  
Destructive Interference ◽  
Latent Heating ◽  
Eastern Canada ◽  
Transient Wave ◽  
The North ◽  
Wave Interference

AbstractThis study examines the role of the latent heating in exciting the upper-level circulation anomaly which destructively interferes with the climatological stationary wave in the Western Hemisphere during boreal summer. This destructive interference pattern closely resembles the circulation trend which is known to be responsible for surface heat extreme trends. To investigate the mechanism behind this circulation anomaly, daily stationary-transient wave interference and related meteorological variables are analyzed using reanalysis data for the period of 1979-2017. Numerical model simulations forced by reanalysis heating anomalies indicate that the destructive interference pattern is most effectively excited by latent heating anomalies over the North Pacific and eastern Canada. The North Pacific heating anomaly drives circulation anomalies that not only resemble the destructive interference pattern, but also transport moisture into eastern Canada. The resulting latent heating over eastern Canada drives circulation that further reinforces the destructive interference pattern which includes a prominent high pressure system over Greenland. Tropical heating also plays a role in driving the destructive interference pattern. On intraseasonal time scales, the destructive interference pattern is preceded by suppressed Indo-western Pacific heating and enhanced North American monsoon heating. On decadal time scales, both heating centers have strengthened, but the trend of the North American monsoon heating was greater than that of the Indo-Western Pacific heating. These uneven heating trends help explain the resemblance between the destructive interference pattern and the circulation trend over the Western Hemisphere.

scholarly journals Comments on “Regional Impacts of Irrigation in Mexico and the Southwestern United States on Hydrometeorological Fields in the North American Monsoon Region”

2018 ◽  
Vol 19 (2) ◽  
pp. 477-481 ◽  
Author(s):  
Theodore J. Bohn ◽  
Enrique R. Vivoni
Keyword(s):  
North American ◽  
Gulf Of California ◽  
Wrf Model ◽  
Summer Precipitation ◽  
Atmospheric Modeling ◽  
Irrigated Agriculture ◽  
North American Monsoon ◽  
Impact Surface ◽  
The North ◽  
The Impact

Abstract For their investigation of the impact of irrigated agriculture on hydrometeorological fields in the North American monsoon (NAM) region, Mahalov et al. used the Weather Research and Forecasting (WRF) Model to simulate weather over the NAM region in the summer periods of 2000 and 2012, with and without irrigation applied to the regional croplands. Unfortunately, while the authors found that irrigated agriculture may indeed influence summer precipitation, the magnitude, location, and seasonality of their irrigation inputs were substantially inaccurate because of 1) the assumption that pixels classified as “irrigated cropland” are irrigated during the summer and 2) an outdated land cover map that misrepresents known agricultural districts. The combined effects of these errors are 1) an overestimation of irrigated croplands by a factor of 3–10 along the coast of the Gulf of California and by a factor of 1.5 near the Colorado River delta and 2) a large underestimation of irrigation by a factor of 7–10 in Chihuahua, particularly in 2012. Given the sensitivity of the WRF simulations conducted by Mahalov et al. to the presence of irrigated agriculture, it is expected that the identified errors would significantly impact surface moisture and energy fluxes, resulting in noticeably different effects on precipitation. The authors suggest that the analysis of irrigation effects on precipitation using coupled land–atmospheric modeling systems requires careful specification of the spatiotemporal distribution of irrigated croplands.

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.

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