DOCSLIB.ORG

4.2 Overview of the North American Monsoon Experiment (Name)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
4.2 Overview of the North American Monsoon Experiment (Name) 4.2 OVERVIEW OF THE NORTH AMERICAN MONSOON EXPERIMENT (NAME) Wayne Higgins* Climate Prediction Center, Camp Springs, MD ABSTRACT 1. OBJECTIVES AND RELEVANCE Recent progress on the North American The North American Monsoon Experiment Monsoon Experiment (NAME) is reviewed, with (NAME) is an internationally coordinated, joint emphasis on plans for a NAME Field Campaign CLIVAR-GEWEX process study aimed at during the NH summer of 2004. NAME is an determining the sources and limits of predictability of internationally coordinated, joint CLIVAR-GEWEX warm season precipitation over North America. It process study aimed at determining the sources and focuses on observing and understanding the key limits of predictability of warm season precipitation components of the North American Monsoon over North America. It hypothesizes that the North System (NAMS) and their variability within the American Monsoon System (NAMS) provides a context of the evolving land surface-atmosphere- physical basis for determining the degree of ocean annual cycle. It seeks improved understanding predictability of warm season precipitation over the of the key physical processes that must be region. NAME employs a multi-scale (tiered) parameterized for improved simulations and approach with focused activities in the core monsoon predictions with coupled models. NAME employs a region (Tier 1), on the regional-scale (Tier 2) and on multi-scale (tiered) approach (Fig. 1) with focused the continental-scale (Tier 3). NAME’s objectives monitoring, diagnostic and modeling activities in the are to promote a better understanding and more core monsoon region, on the regional-scale and on realistic simulation of: warm season convective the continental-scale. NAME is part of the processes in complex terrain (Tier 1); the CLIVAR/VAMOS program, US CLIVAR Pan intraseasonal variability of the monsoon (Tier 2); and American research, and the GEWEX Americas the response of the warm season precipitation pattern Prediction Project (GAPP). to slowly varying oceanic and continental boundary conditions (Tier 3). NAME Science is managed by a NORTH AMERICAN MONSOON EXPERIMENT (NAME) Science Working Group (SWG) made up of scientists Topographic and HYPOTHESIS from the U.S., Mexico and Central America, both Sea-Land Influence The NAMS provides a physical basis for determining the degree of university and government. NAME has an eight year predictability of warm season life cycle (2000-2008) including build-up, field, precipitation over the region. OBJECTIVES: Intraseasonal analysis and modeling phases. The NAME program Variability Better understanding and simulation of: has strong links between the VAMOS element of • warm season convective International CLIVAR, US CLIVAR Pan American processes in complex terrain (TIER I); research, and the GEWEX Americas Prediction • intraseasonal variability of Boundary the monsoon (TIER II); Project (GAPP). An online version of the NAME Forcing? • response of warm season circulation and precipitation Science and Implementation Plan is available at to slowly varying boundary YEAR (2000+) 00 01 02 03 04 05 06 07 08 conditions (SST, soil Planning --------------| http://www.joss.ucar.edu/name moisture) (TIER III); Preparations --------------| • monsoon evolution and Data Collection - - - ----------------| variability (TIER I, II, III). Principal Research ----------------------------------| Data Management -----------------------------------------| *Corresponding Author Address: Wayne Higgins, Figure 1. Schematic Illustrating the multi-tiered Climate Prediction Center /NCEP/NWS/NOAA, approach, timeline and objectives of the North Camp Springs, MD, 20746 American Monsoon Experiment (NAME). [email protected] The scientific objectives of NAME are to promote a better understanding and more realistic simulation of: 1 preserve the modeling-observations linkage for both $ warm season convective processes in communities (see section 4). The Teams consist of complex terrain (Tier 1); NAME observationalists, process modelers, and $ intraseasonal variability of the monsoon physical parameterization specialists at the US (Tier 2); national climate modeling and prediction centers. $ the response of the warm season Some key questions to be addressed by the NAME atmospheric circulation and precipitation Teams include: patterns to slowly varying, potentially predictable surface boundary conditions $ How well is the life cycle of the monsoon (e.g. SST, soil moisture) (Tier 3); (onset, maintenance and demise) simulated $ the evolution of the North American monsoon and predicted? system and its variability; $ What is the nature of the interactions between the diurnal cycle and the evolution To accomplish these objectives, planning has of the North American summer monsoon proceeded with the intent of developing: system? $ How well do models simulate convective $ empirical and modeling studies that carry processes in complex terrain? forward the joint US CLIVAR/GEWEX Warm Season Precipitation Initiative (2000 onward), and initiate new elements; $ a NAME Enhanced Observing Period (JJAS 2004) including build-up, field, analysis and modeling phases. An online version of the NAME Science and Implementation Plan is available from the NAME Web site at UCAR Joss: http://www.joss.ucar.edu/name/ 1.1. Key questions, issues and/or hypotheses the study will address NAME hypothesizes that the North American Monsoon System (NAMS) provides a Figure 2. Schematic vertical (longitude-pressure) physical basis for determining the degree of cross section through the North American Monsoon predictability of warm season precipitation over the System at 27.5N. Topography data was used to region. NAME emphasizes the role of the land establish the horizontal scale and NCEP/NCAR surface (e.g. topographic influences on precipitation; Reanalysis wind and divergence fields were used to hydrology and water resources; land surface memory establish the vertical circulations. processes), the role of low-level jets (e.g. relationships between the Gulf of California LLJ, moisture surges and the diurnal cycle of $ What is the connection between synoptic precipitation) (Fig. 2), and the role of oceanic forcing variability over nearby oceans (e.g. easterly of continental climate anomalies (e.g. remote versus waves) and the development of Gulf surges local SST’s; antecedent influences; influence of the and continental precipitation? leading patterns of climate variability, including $ What are the links, if any, between the ENSO, MJO, PDO). strength of the monsoon in SW North America and summertime precipitation over NAME’s scientific questions are motivated the central US? by the current warm season predictive capabilities, $ How is the evolution of the warm season science issues and observational needs of the global precipitation regime related to the seasonal and regional modeling communities. To make evolution of continental and oceanic progress, NAME has organized two Teams that boundary conditions? 2 $ Can models reproduce the observed $ NAME Program Management (funding summertime precipitation in average years agencies) and years with ENSO influence? NAME science is managed by a SWG that has been approved by the CLIVAR/VAMOS and CLIVAR Addressing these questions will yield a better Pan American panels in consultation with U.S. understanding of what physical processes need to be GEWEX. The SWG develops and leads research to included in climate models in order to reproduce the achieve NAME objectives. monsoon system. Consideration of these questions will also help to identify needs for additional The NAME Project Office at UCAR/JOSS, observations. led by Dr. C. B. Emmanuel, is responsible for the following NAME functions: 1.2. Responsiveness of the process $ Program Planning and Field Implementation: Provide the infrastructure NAME is directly responsive to CLIVAR for effective design and implementation of science goals. In May 2001 the Pan Am Panel the NAME EOP, including management of recommended that US CLIVAR join with US GAPP field operations. and VAMOS to implement NAME as a warm season $ Scientific Data Management: Provide all process study of the North American monsoon built facets of data collection and dissemination around an Enhanced Observing Period during 2004. of information for the NAME Program. US CLIVAR’s primary interests and contributions to $ Logistics: Provide specialized logistics NAME were listed in the meeting report. These support specifically for the effective interests would lead to the following CLIVAR- implementation of the NAME EOP, NAME deliverables: including administrative support, workshop coordination and outreach (e.g. webpage, $ improved coupled climate models capable of logo). predicting North American monsoon variability months to seasons in advance; The NAME science objectives will be addressed by a $ more comprehensive understanding of North symbiotic mix of diagnostic, modeling and prediction American summer climate variability and studies together with enhanced observations (all predictability; approved by the NAME SWG). NAME employs a $ infrastructure to observe and monitor the multi-scale (tiered) approach with focused North American monsoon system; monitoring, diagnostic and modeling activities in the $ contributions to the assessment of climate core monsoon region (Tier 1), on the regional-scale variability and long-term climate change in (Tier 2) and on the continental-scale (Tier 3). the North American monsoon region; $ strengthened multinational scientific
Load more

Recommended publications
  • Chapter 7: Circulation and the Atmosphere
    1/27/2016 Chapter 7: Circulation And The Atmosphere Highly integrated wind system Main Circulation Currents: series of deep rivers of air encircling the planet Various perturbations or vortices (hurricanes, tornados, cyclones) Scales of Atmospheric Motion: -based on time and space -Macorscale: encompass global wind patterns (westerlies, trades) through hurricanes (hours on up) -Mesoscale: Tornados, thunder storms, local winds (minutes-hours) -Microscale: wind gusts, dust devils (seconds – minutes) 1 1/27/2016 Macorscale Planetary-scale: global winds stable for weeks to months Synoptic-scale: weather map scale migrating cyclones/anticyclones, hurricanes days-weeks, 100s – 1000s km Mesoscale: Small disturbances < 100 km, minutes-hours Travel embedded within the larger macroscale circulation ex. ((thunderstorm) hurricane) westerlies) 2 1/27/2016 Microscale: wind gusts, dust devils (seconds – minutes) Mesoscale All Winds: arise from pressure gradients resulting from unequal heating of the surface Local Winds: arise from local pressure gradients Sea & Land Breeze Mountain & Valley Breeze Chinook Winds Katabatic Winds Country Breeze The Haboob 3 1/27/2016 Mesoscale Sea Breeze: air over land expands as heated during day, develop L temperature can decrease 5-10 deg. C 30 – 60 miles inland Mesoscale Land Breeze: air over land cools quicker during the evening, develop H result in reverse circulation offshore wind 4 1/27/2016 Mesoscale Valley Breeze: Slopes warm faster than air at same elevation over the valley Flow from the valley to the mountains Most common in summer, intense heating Mesoscale Mountain Breeze: Slopes cool faster after sundown Flow from the mountains to the valley Most common in winter, radiation cooling 5 1/27/2016 Mesoscale Chinook Winds: Warm dry winds on the leeward slopes of mountains Adiabatic warming Eastward slopes of Rockies Santa-Ana Winds, Southern California Mesoscale Katabatic (Fall) Winds: Cold dense air over highland area Descends, displacing less dense air Attain velocities capable of destruction ex.
    [Show full text]
  • North American Monsoon Precipitation Reconstructed from Tree-Ring Latewood Daniel Griffin,1,2 Connie A
    GEOPHYSICAL RESEARCH LETTERS, VOL. 40, 1–5, doi:10.1002/grl.50184, 2013 North American monsoon precipitation reconstructed from tree-ring latewood Daniel Griffin,1,2 Connie A. Woodhouse,1,2 David M. Meko,1 David W. Stahle,3 Holly L. Faulstich,1,2 Carlos Carrillo,4 Ramzi Touchan,1 Christopher L. Castro,4 and Steven W. Leavitt1 Received 30 November 2012; revised 18 January 2013; accepted 21 January 2013. [1] The North American monsoon is a major focus of paleoclimatology [e.g., Asmerom et al., 2007; Barron et al., modern and paleoclimate research, but relatively little is 2012], but relatively little is known about pre-instrumental known about interannual- to decadal-scale monsoon monsoon variability at interannual to decadal timescales. moisture variability in the pre-instrumental era. This study Understanding the plausible range of monsoon variability is draws from a new network of subannual tree-ring latewood critical because model projections of monsoon response to width chronologies and presents a 470-year reconstruction anthropogenic greenhouse gas forcing remain unclear of monsoon (June–August) standardized precipitation for [Castro et al., 2012; Bukovsky and Mearns, 2012; Cook southwestern North America. Comparison with an and Seager, 2013]. The American Southwest has a rich independent reconstruction of cool-season (October–April) history of dendroclimatology, but the vast majority of tree-ring standardized precipitation indicates that southwestern reconstructions from the region reflect only cool-season or decadal droughts of the last five centuries were characterized annual-scale moisture variability. This is epitomized by the not only by cool-season precipitation deficits but also by North American Drought Atlas, which, for the Southwest, concurrent failure of the summer monsoon.
    [Show full text]
  • In This Paper We Review Evidence for Climatic Variability Across the North American Monsoon (NAM) Region Over the Holocene and C
    Aberystwyth University The Holocene history of the North American Monsoon: 'known knowns' and 'known unknowns' in understanding its spatial and temporal complexity Metcalfe, Sarah E.; Barron, John A.; Davies, Sarah J. Published in: Quaternary Science Reviews DOI: 10.1016/j.quascirev.2015.04.004 Publication date: 2015 Citation for published version (APA): Metcalfe, S. E., Barron, J. A., & Davies, S. J. (2015). The Holocene history of the North American Monsoon: 'known knowns' and 'known unknowns' in understanding its spatial and temporal complexity. Quaternary Science Reviews, 120, 1-27. https://doi.org/10.1016/j.quascirev.2015.04.004 General rights Copyright and moral rights for the publications made accessible in the Aberystwyth Research Portal (the Institutional Repository) are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the Aberystwyth Research Portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the Aberystwyth Research Portal Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. tel: +44 1970 62 2400 email: [email protected] Download date: 29. Sep. 2021 The Holocene history of the North American Monsoon: ’known knowns’ and ‘known unknowns’ in understanding its spatial and temporal complexity Sarah E.
    [Show full text]
  • 3.6 Educating the Public on the North American Monsoon System
    3.6 EDUCATING THE PUBLIC ON THE NORTH AMERICAN MONSOON SYSTEM Glen Sampson* and Erik Pytlak National Weather Service, Tucson, Arizona 1. INTRODUCTION most of the stations in Arizona received rain, the monsoon would be declared as “being here” In Arizona the weather event of the year, (Tenharkel 1980). every year, is the North American Monsoon. Another method used to declare the monsoon During May and June temperatures soar to well was dew point temperatures. Three consecutive over 100oF throughout much of the state and days of 55oF or higher at the Phoenix airport was conditions are extremely dry with relative humidity used to indicate the monsoon had started. in the single digits. Vegetation becomes heat Likewise, monsoon days (days with an average stressed as the landscape turns brown. dew point higher than 55oF) could be counted and These conditions, along with blistering an end to the monsoon could be declared sunshine for days on end, cause people to long for (Skindlov 2007). clouds in the sky, the scent of rain in the air and the cool breeze from a thunderstorm outflow. The 2.1 Faults of these historical methods monsoon is also the time of year in which the most weather-related fatalities, injuries and damage All of these historical methods were an after- occur across Arizona from flash floods, lightning, the-fact analysis of what happened in Arizona dust storms, straight line winds, and persistent associated with the monsoon system. All of them heat outside of the active thunderstorm days failed to accurately represent what was truly (Shoemaker and Davis 2008).
    [Show full text]
  • North American Monsoon By: Ryan Nicoll, ADEQ Air Quality Meteorologist the AQ Code”    the North American Monsoon Has a Major Influence on Arizona’S Weather
    Cracking the AQ Code Air Quality Forecast Team September 2015 Volume 1, Issue 3 About “Cracking The North American Monsoon By: Ryan Nicoll, ADEQ Air Quality Meteorologist the AQ Code” The North American Monsoon has a major influence on Arizona’s weather. “Monsoon” is a common term used in Arizona and the In an effort to further greater southwestern United States, but it is often used incorrectly. ADEQ’s mission of Our hope is that this discussion will increase your understanding of protecting and enhancing what a monsoon is and the crucial part it plays in shaping not only the public health and the region’s weather, but also its air quality. environment, the Forecast What is (and isn’t) a monsoon? Team has decided to Fig. 1 : This graph represents the vertical cross Much like the hurricane season, the North American Monsoon also produce periodic, in-depth section of earth’s atmosphere. Note the has specific start and end dates. The monsoon season officially articles about various topics difference in thickness between the layers and how temperatures (red line) warm or cool with runs from June 15 through September 30, although the monsoon related to weather and air height throughout each layer. The stratospheric pattern can set up earlier or end later than this period. Technically quality. warming is primarily due to the ozone layer speaking, a monsoon is a seasonal shift in the prevailing wind which absorbs UV light from the sun. pattern which results in a significant change in precipitation. In the Our hope is that these Source: Four Interconnecting Spheres case of the North American Monsoon, the typical southwesterly articles provide you with a (blowing from the southwest) synoptic flow shifts southeasterly, better understanding of driving mid-level moisture from the Gulf of Mexico into Arizona.
    [Show full text]
  • Interannual Variability of the Bimodal Distribution of Summertime Rainfall Over Central America and Tropical Storm Activity in the Far-Eastern Pacific
    CLIMATE RESEARCH Vol. 22: 141–146, 2002 Published September 6 Clim Res Interannual variability of the bimodal distribution of summertime rainfall over Central America and tropical storm activity in the far-eastern Pacific Scott Curtis* Joint Center for Earth Systems Technology, University of Maryland, Baltimore County, Department of Geography, NASA/Goddard Space Flight Center, Code 912, Greenbelt, Maryland 20771, USA ABSTRACT: The summer climate of southern Mexico and Central America is characterized by a mid- summer drought (MSD), where rainfall is reduced by 40% in July as compared to June and Septem- ber. A mid-summer reduction in the climatological number of eastern Pacific tropical cyclones has also been noted. Little is understood about the climatology and interannual variability of these min- ima. The present study uses a novel approach to quantify the bimodal distribution of summertime rainfall for the globe and finds that this feature of the annual cycle is most extreme over Pan America and adjacent oceans. One dominant interannual signal in this region occurs the summer before a strong winter El Niño/Southern Oscillation (ENSO). Before El Niño events the region is dry, the MSD is strong and centered over the ocean, and the mid-summer minimum in tropical cyclone frequency is most pronounced. This is significantly different from Neutral cases (non-El Niño and non-La Niña), when the MSD is weak and positioned over the land bridge. The MSD is highly variable for La Niña years, and there is not an obvious mid-summer minimum in the number of tropical cyclones. KEY WORDS: Rainfall · Tropical storms · Summer · Central America · ENSO Resale or republication not permitted without written consent of the publisher 1.
    [Show full text]
  • Lightning in the North American Monsoon: an Exploratory Climatology
    1970 MONTHLY WEATHER REVIEW VOLUME 143 Lightning in the North American Monsoon: An Exploratory Climatology RONALD L. HOLLE Vaisala, Inc., Tucson, Arizona MARTIN J. MURPHY Vaisala, Inc., Louisville, Colorado (Manuscript received 29 October 2014, in final form 19 January 2015) ABSTRACT Temporal and spatial distributions of the North American monsoon have been studied previously with rainfall and satellite data. In the current study, the monsoon is examined with lightning data from Vaisala’s Global Lightning Dataset (GLD360). GLD360 has been operating for over three years and provides sufficient data to develop an exploratory climatology with minimal spatial variation in detection efficiency and location accuracy across the North American monsoon region. About 80% of strokes detected by GLD360 are cloud to ground. This paper focuses on seasonal, monthly, and diurnal features of lightning occurrence during the monsoon season from Mazatlán north-northwest to northern Arizona and New Mexico. The goal is to describe thunderstorm frequency with a dataset that provides uniform spatial coverage at a resolution of 2–5 km and uniform temporal coverage with individual lightning events resolved to the millisecond, compared with prior studies that used hourly point rainfall or satellite data with a resolution of several kilometers. The monthly lightning stroke density over northwestern Mexico increases between May and June, as thunderstorms begin over the high terrain east of the Gulf of California. The monthly lightning stroke density over the entire region increases dramatically to a maximum in July and August. The highest stroke densities observed in Mexico approach those observed by GLD360 in subtropical and tropical regions in Africa, Central and South America, and Southeast Asia.
    [Show full text]
  • Hydroclimatology of the North American Monsoon Region in Northwest Mexico
    J6.7 HYDROCLIMATOLOGY OF THE NORTH AMERICAN MONSOON REGION IN NORTHWEST MEXICO David J. Gochis National Center for Atmospheric Research, Boulder, CO, USA Luis Brito-Castillo Centro de Investigaciones Biologicas del Noroeste (CIBNOR), Guaymas, Sonora, Mexico W. James Shuttleworth Department of Hydrology and Water Resourece, University of Arizona, Tucson, AZ, USA 1.1 INTRODUCTION 2. DATA AND METHODS The region of northwest Mexico is generally 2.1. Data semi-arid, with an annual precipitation regime dominated by warm-season convection that Selected basins draining the SMO are strongly interacts with the regional topography shown in Figure 1. Monthly streamflow data and surrounding bodies of water. The were obtained from the BANDAS (Banco summertime monsoonal circulation, its onset, Nacional de Datos de Aguas Superficiales) data precipitation character, and the hydrological archive, BANDAS (1998). Streamflow periods response to it, exhibit considerable spatial and of record vary for individual basins, but all basins temporal variability. This variability complicates possess a minimum of 10 years of data. The diagnostic and predictive efforts and limits size of these catchments studied in the present adaptive management of regional water analysis range from 1,000 – 10,000 km2 and are resources. This work explores the complex unregulated. Thus, the results presented herein relationship between precipitation and are constrained to focus on the “natural” streamflow in the North American Monsoon hydrological response of typical SMO headwater (NAM) region by constructing a regional catchments to monsoon rains. Three of the 15 hydroclimatology from selected headwater basins studied (1. Rio San Pedro del Conchos, catchments from northwest Mexico. 7. Rio Sextin, and 11.
    [Show full text]
  • Global Circulation
    ESCI 241 – Meteorology Lesson 14 – Global Circulation THE GLOBAL CIRCULATION Latitudinal heat imbalance – The tropics receive more radiation than they emit. The polar regions emit more radiation than they receive. This causes an imbalance in heat. If there were no heat transferred between the tropics and the polar regions, the tropics would get hotter and hotter, while the poles would get colder and colder. THE LATITUDINAL HEAT IMBALANCE IS WHAT DRIVES THE CIRCULATION OF THE ATMOSPHERE AND OCEANS. ο THE CIRCULATION OF THE ATMOSPHERE AND OCEANS BOTH ACT TO TRANSFER HEAT FROM THE TROPICS TO THE POLES . One way to accomplish the transfer of heat from the equator to the poles would be to have a single circulation cell that was upward in the tropics, poleward aloft, downward at the poles, and equatorward at the surface. This is the single- cell circulation model first proposed by Hadley in the 1700’s. Because the earth rotates, instead of a single-cell circulation there is a three-cell circulation. Because the Coriolis force act to the right of the flow (in the Northern Hemisphere), the flow around the 3-cells is deflected. This gives rise to the three main wind belts in each hemisphere at the surface: ο The easterly trade winds in the tropics ο The prevailing westerlies ο The polar easterlies The doldrums are the region near the equator where the trade winds from each hemisphere meet. This is also where you find the intertropical convergence zone (ITCZ) . It is characterized by hot, humid weather with light winds. The horse latitudes are the region between the trade winds and the prevailing westerlies.
    [Show full text]
  • Land Surface Ecohydrology of the North American Monsoon System
    LAND SURFACE ECOHYDROLOGY OF THE NORTH AMERICAN MONSOON SYSTEM Special Issue in Journal of Arid Environments, May 2010 Synthesis and Introduction by Enrique R. Vivoni School of Earth and Space Exploration Arizona State University, Tempe, AZ BACKGROUND Ecohydrological studies in the southwest U.S. and northwest Mexico benefit from bi-national research programs (e.g., SALSA, NAME, SMEX04). Prior studies across the U.S.-Mexico border have highlighted the close interactions between water and ecosystems in determining land surface conditions. This special issue was designed to bring together U.S. and Mexico studies on ecohydrology initiated during NAME and SMEX04. APPROACH TODAY Introduce and summarize the major findings from a selected number of the twelve papers. Proceed in an order that spans from the entire regions to specific sites and from observational to modeling. Key included with Study Area, Topics & Institutions Present a synthesis of the special issue that points to future research paths. For more information, see preface article: Vivoni, E.R., Watts, C.J. and Gochis, D.J. 2010. Land surface ecohydrology of the North American Monsoon system, Journal of Arid Environments, 74, 529-530. BRITO-CASTILLO ET AL: AN ANOMALY IN THE OCCURRENCE OF THE MONTH OF MAXIMUM PRECIPITATION IN NORTHWEST MEXICO Motivation: Rainfall in northwest Mexico reveals a disruption in the south to north progression. This study tests hypotheses explaining this rainfall anomaly. Question: What factors control the peak rainfall activity in western Mexico and the Mexican Antiplano? Long-term rainfall and streamflow observations used to identify the rainfall anomaly and its hydrologic implications. Sea-surface temperature and terrain distributions aid in testing a set of potential hypotheses.
    [Show full text]
  • Compendium on Tropical Meteorology for Aviation Purposes
    Compendium on Tropical Meteorology for Aviation Purposes 2020 edition WEATHER CLIMATE WATER CLIMATE WEATHER WMO-No. 930 Compendium on Tropical Meteorology for Aviation Purposes 2020 edition WMO-No. 930 EDITORIAL NOTE METEOTERM, the WMO terminology database, may be consulted at https://public.wmo.int/en/ meteoterm. Readers who copy hyperlinks by selecting them in the text should be aware that additional spaces may appear immediately following http://, https://, ftp://, mailto:, and after slashes (/), dashes (-), periods (.) and unbroken sequences of characters (letters and numbers). These spaces should be removed from the pasted URL. The correct URL is displayed when hovering over the link or when clicking on the link and then copying it from the browser. WMO-No. 930 © World Meteorological Organization, 2020 The right of publication in print, electronic and any other form and in any language is reserved by WMO. Short extracts from WMO publications may be reproduced without authorization, provided that the complete source is clearly indicated. Editorial correspondence and requests to publish, reproduce or translate this publication in part or in whole should be addressed to: Chair, Publications Board World Meteorological Organization (WMO) 7 bis, avenue de la Paix Tel.: +41 (0) 22 730 84 03 P.O. Box 2300 Fax: +41 (0) 22 730 81 17 CH-1211 Geneva 2, Switzerland Email: [email protected] ISBN 978-92-63-10930-9 NOTE The designations employed in WMO publications and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of WMO concerning the legal status of any country, territory, city or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries.
    [Show full text]
  • Seasonal Analysis of the 2011–2017 North American Monsoon Near Its Northwest Boundary
    atmosphere Article Seasonal Analysis of the 2011–2017 North American Monsoon near its Northwest Boundary Charles Truettner 1, Michael D. Dettinger 2,3, Emanuele Ziaco 1 and Franco Biondi 1,* 1 DendroLab, Department of Natural Resources and Environmental Science, University of Nevada, Reno, NV 89557, USA 2 U.S. Geological Survey (Retired), Carson City, NV 89701, USA 3 Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92037, USA * Correspondence: [email protected] Received: 14 June 2019; Accepted: 16 July 2019; Published: 21 July 2019 Abstract: The seasonal extent of the North American Monsoon (NAM) is highly variable and potentially sensitive to future climate change. Our objective was to determine how regional monsoonal patterns influence mountain precipitation near the NAM northwest boundary. Among the data we analyzed, a unique opportunity was provided by hourly observations collected on the Sheep Range (2300 m asl), in the Mojave Desert of southern Nevada, during 2011–2017. Long-term 800-m Parameter-elevation Relationships on Independent Slopes Model (PRISM) precipitation time series showed that the site is representative of mountain areas in the NAM northwest region. Based on in situ observations, we divided the water year into three seasons: cool (1 October through 31 March), early warm (1 April through last day with dewpoint <9.4 ◦C), and late warm (first day with dewpoint 9.4 C through 30 September). Dewpoint temperature differed by about 8 C between early warm ≥ ◦ ◦ season (mean of 6.3 C) and late warm season (mean of 2.3 C). According to ANCOVA model − ◦ ◦ results, increasing hourly dewpoint associated with afternoon thunderstorms in the late warm season had the greatest relationship with hourly precipitation (F-value = 237.8, p-value < 0.01).
    [Show full text]