RAL

Food security report wins USDA award

BOULDER, Colo. — A comprehensive report warning of the impacts of climate change on the world's food security has won a top U.S. Department of Agriculture (USDA) award."Climate Change, Global Food Security, and the U.S. Food System," with co-authors from the National Center for Atmospheric Research (NCAR), provides an overview of recent research in climate change and agriculture. It warns that warmer temperatures and altered precipitation patterns can threaten food production, disrupt transportation systems, and degrade food safety, among other impacts, and that the world's poor and those living in tropical regions are particularly vulnerable.Michael Scuse, USDA acting deputy secretary (center), with members of the team of experts who produced the award-winning report, "Climate Change, Global Food Security, and the U.S. Food System." Those pictured are (back row from left): William Easterling (The Pennsylvania State University), Edward Carr (Clark University), and Peter Backlund (Colorado State University); front row from left: Rachel Melnick (USDA), Margaret Walsh (USDA), Scuse, Moffat Ngugi (U.S. Agency for International Development/USDA), and Karen Griggs (NCAR). (Photo by USDA.) The USDA this month named it as the winner of the 2016 Abraham Lincoln Honor Award for Increasing Global Food Security. The Abraham Lincoln Honor Award is the most prestigious USDA award presented by the Secretary of Agriculture, recognizing noteworthy accomplishments that significantly contribute to the advancement of the USDA's strategic goals, mission objectives, and overall management excellence.The report was produced as part of a collaboration between NCAR, the USDA, and the University Corporation for Atmospheric Research (UCAR), which manages NCAR on behalf of the National Science Foundation. It was written by 32 experts from 19 federal, academic, nongovernmental, intergovernmental, and private organizations in the United States, Argentina, Britain, and Thailand. The authors included three NCAR scientists, as well as eight experts affiliated with UCAR member universities."This award highlights the importance of addressing climate change in order to maintain the progress the world has made on food security in recent decades," said NCAR program director Lawrence Buja, who helped oversee production of the report. "Scientists will continue to study this critical issue and work with decision makers to co-develop the information they need about potential climate impacts on future production, distribution, and other aspects of our U.S. and global food systems."Published under the auspices of the U.S. Global Change Research Program, the reportfocuses on identifying climate change impacts on global food security through 2100. The authors emphasize that food security — the ability of people to obtain and use sufficient amounts of safe and nutritious food — will be affected by several factors in addition to climate change, such as technological advances, increases in population, the distribution of wealth, and changes in eating habits."Climate change has a myriad of potential impacts, especially on food, water, and energy systems," said UCAR President Antonio J. Busalacchi. "I commend the authors of this report for clearly analyzing this very complex issue in the agriculture sector, which has implications for all of society, from the least developed nations to the most advanced economies."Report authorsMolly Brown, University of Maryland*John Antle, Oregon State University*Peter Backlund, Colorado State University *Edward Carr, Clark UniversityBill Easterling, Pennsylvania State University*Margaret Walsh, USDA Office of the Chief Economist/Climate Change Program OfficeCaspar Ammann, NCARWitsanu Attavanich, Kasetsart UniversityChris Barrett, Cornell University*Marc Bellemare, University of Minnesota*Violet Dancheck, U.S. Agency for International DevelopmentChris Funk, U.S. Geological SurveyKathryn Grace, University of Utah*John Ingram, University of OxfordHui Jiang, USDA Foreign Agricultural ServiceHector Maletta, Universidad de Buenos AiresTawny Mata, USDA/American Association for the Advancement of ScienceAnthony Murray, USDA-Economic Research ServiceMoffatt Ngugi, U.S. Agency for International Development/USDA Foreign Agricultural ServiceDennis Ojima, Colorado State University*Brian O'Neill, NCARClaudia Tebaldi, NCAR*UCAR member universityReport project teamLawrence Buja, NCARKaren Griggs, NCAR 

Solar energy gets boost from new forecasting system

BOULDER, Colo. — A cutting edge forecasting system developed by a national team of scientists offers the potential to save the solar energy industry hundreds of millions of dollars through improved forecasts of the atmosphere.The new system, known as Sun4CastTM, has been in development for three years by the National Center for Atmospheric Research (NCAR) in collaboration with government labs, universities, utilities, and commercial firms across the country. Funded by the U.S. Department of Energy SunShot Initiative, the system greatly improves predictions of clouds and other atmospheric conditions that influence the amount of energy generated by solar arrays.After testing Sun4Cast at multiple sites, the research team has determined that it can be up to 50 percent more accurate than current solar power forecasts. This improved accuracy will enable utilities to deploy solar energy more reliably and inexpensively, reducing the need to purchase energy on the spot market. The amount of energy gathered by solar panels — such as these in Colorado's San Luis Valley — is influenced by factors including the position and types of clouds, the amount of snow on the ground, and relative humidity. The new Sun4Cast system greatly improves solar irradiance predictions, enabling utilities to deploy solar energy more reliably and inexpensively. (©UCAR. Photo by Sue Ellen Haupt, NCAR. This image is freely available for media & nonprofit use.)As a result, utilities across the United States may be able to save an estimated $455 million through 2040 as they use more solar energy, according to an analysis by NCAR economist Jeffrey Lazo.NCAR, which does not provide operational forecasts, makes the technology available so it can be adapted by utilities or private forecasting companies. The research is being highlighted in more than 20 peer-reviewed papers."These results can help enable the nation's expanding use of solar energy," said Sue Ellen Haupt, director of NCAR’s Weather Systems and Assessment Program, who led the research team. "More accurate predictions are vital for making solar energy more reliable and cost effective."The work builds on NCAR’s expertise in highly detailed atmospheric prediction, including the design of an advanced wind energy forecasting system."This type of research and development is important because it contributes to the reduction in costs for solar and wind energy and makes it easier for utilities to integrate renewables into the electrical grid," said William Mahoney, Deputy Director of NCAR's Research Applications Laboratory. "When it comes to balancing demand for power with supply, it's vital to be able to predict sources of energy as accurately as possible."Xcel Energy is already beginning to use the system to forecast conditions at several of its main solar facilities.“Our previous experience with the National Center for Atmospheric Research in developing a wind forecasting system has saved millions of dollars and has been highly beneficial for our customers," said Drake Bartlett, senior trading analyst for Xcel Energy – Colorado. "It is our sincere hope and belief that we will see positive atmospheric forecasting results for predicting solar generation as well, again to the benefit of our Xcel Energy customers."Energy forecasts out to 72 hoursUsing a combination of advanced computer models, atmospheric observations, and artificial intelligence techniques, Sun4Cast provides 0- to 6-hour nowcasts of solar irradiance and the resulting power production for specific solar facilities at 15-minute intervals. This enables utilities to continuously anticipate the amount of available solar energy.In addition, forecasts extend out to 72 hours, allowing utility officials to make decisions in advance for balancing solar with other sources of energy.Solar irradiance is notoriously difficult to predict. It is affected not just by the locations and types of clouds, but also a myriad of other atmospheric conditions, such as the amount of dust and other particles in the air, relative humidity, and air pollution. Further complicating the forecast, freshly fallen snow, nearby steep mountainsides, or even passing cumulus clouds can reflect sunlight in a way that can increase the amount of energy produced by solar panels.To design a system to forecast solar energy output, NCAR and its partners drew on an array of observing instruments, including satellites, radars, and sky imagers; specialized software; and mathematical and artificial intelligence techniques. Central to Sun4Cast is a new computer model of the atmosphere that simulates solar irradiance based on meteorological conditions. Called WRF-SolarTM, the model is derived from the NCAR-based Weather Research and Forecasting (WRF) model, which is widely used by meteorological agencies worldwide.The team tested the system in geographically diverse areas, including Long Island, New York; the Colorado mountains; and coastal California."We have to provide utilities with confidence that the system maintains a high degree of accuracy year-round in very different types of terrain," said Branko Kosovic, NCAR Program Manager for Renewable Energy.In addition to aiding the solar power industry, the work can also improve weather forecasting in general because of improved cloud prediction.NCAR's numerous partners on the project in the public and private sectors included:Government labs: National Renewable Energy Laboratory, Brookhaven National Laboratory, the National Oceanic and Atmospheric Administration’s Earth System Research Laboratory, and other NOAA facilities; Universities: The Pennsylvania State University, Colorado State University, University of Hawaii, and University of Washington; Utilities: Long Island Power Authority, New York Power Authority, Public Service Company of Colorado, Sacramento Municipal Utility District (SMUD), Southern California Edison, and the Hawaiian Electric Company; Independent system operators: New York ISO, Xcel Energy, SMUD, California ISO, and Hawaiian Electric; and Commercial forecast providers: Schneider Electric, Atmospheric and Environmental Research, Global Weather Corporation, MDA Information Systems, and Solar Consulting Services.Computing time was provided by the New York State Department of Economic Development's Division of Science, Technology and Innovation on an IBM Blue Gene supercomputer at Brookhaven National Laboratory. Researchers also performed computing at the NCAR-Wyoming Supercomputing Center and the DOE National Energy Research Scientific Computing Center.About the SunShot InitiativeThe U.S. Department of Energy SunShot Initiative is a collaborative national effort that aggressively drives innovation to make solar energy fully cost-competitive with traditional energy sources before the end of the decade. Through SunShot, the Energy Department supports efforts by private companies, universities, and national laboratories to drive down the cost of solar electricity to $0.06 per kilowatt-hour.

US taps NCAR technology for new water resources forecasts

BOULDER, Colo. — As the National Oceanic and Atmospheric Administration (NOAA) this month launches a comprehensive system for forecasting water resources in the United States, it is turning to technology developed by the National Center for Atmospheric Research (NCAR) and its university and agency collaborators.WRF-Hydro, a powerful NCAR-based computer model, is the first nationwide operational system to provide continuous predictions of water levels and potential flooding in rivers and streams from coast to coast. NOAA's new Office of Water Prediction selected it last year as the core of the agency's new National Water Model."WRF-Hydro gives us a continuous picture of all of the waterways in the contiguous United States," said NCAR scientist David Gochis, who helped lead its development. "By generating detailed forecast guidance that is hours to weeks ahead, it will help officials make more informed decisions about reservoir levels and river navigation, as well as alerting them to dangerous events like flash floods."WRF-Hydro (WRF stands for Weather Research and Forecasting) is part of a major Office of Water Prediction initiative to bolster U.S. capabilities in predicting and managing water resources. By teaming with NCAR and the research community, NOAA's National Water Center is developing a new national water intelligence capability, enabling better impacts-based forecasts for management and decision making.The new WRF-Hydro computer model simulates streams and other aspects of the hydrologic system in far more detail than previously possible. (Image by NOAA Office of Water Prediction.) Unlike past streamflow models, which provided forecasts every few hours and only for specific points along major river systems, WRF-Hydro provides continuous forecasts of millions of points along rivers, streams, and their tributaries across the contiguous United States. To accomplish this, it simulates the entire hydrologic system — including snowpack, soil moisture, local ponded water, and evapotranspiration — and rapidly generates output on some of the nation's most powerful supercomputers.WRF-Hydro was developed in collaboration with NOAA and university and agency scientists through the Consortium of Universities for the Advancement of Hydrologic Science, the U.S. Geological Survey, Israel Hydrologic Service, and Baron Advanced Meteorological Services. Funding came from NOAA, NASA, and the National Science Foundation, which is NCAR's sponsor."WRF-Hydro is a perfect example of the transition from research to operations," said Antonio (Tony) J. Busalacchi, president of the University Corporation for Atmospheric Research, which manages NCAR on behalf of the National Science Foundation (NSF). "It builds on the NSF investment in basic research in partnership with other agencies, helps to accelerate collaboration with the larger research community, and culminates in support of a mission agency such as NOAA. The use of WRF-Hydro in an operational setting will also allow for feedback from operations to research. In the end this is a win-win situation for all parties involved, chief among them the U.S. taxpayers.""Through our partnership with NCAR and the academic and federal water community, we are bringing the state of the science in water forecasting and prediction to bear operationally," said Thomas Graziano, director of NOAA’s new Office of Water Prediction at the National Weather Service.Filling in the water pictureThe continental United States has a vast network of rivers and streams, from major navigable waterways such as the Mississippi and Columbia to the remote mountain brooks flowing from the high Adirondacks into the Hudson River. The levels and flow rates of these watercourses have far-reaching implications for water availability, water quality, and public safety.Until now, however, it has not been possible to predict conditions at all points in the nation's waterways. Instead, computer models have produced a limited picture by incorporating observations from about 4,000 gauges, generally on the country's bigger rivers. Smaller streams and channels are largely left out of these forecast models, and stretches of major rivers for tens of miles are often not predicted — meaning that schools, bridges, and even entire towns can be vulnerable to unexpected changes in river levels.To fill in the picture, NCAR scientists have worked for the past several years with their colleagues within NOAA, other federal agencies, and universities to combine a range of atmospheric, hydrologic, and soil data into a single forecasting system.The resulting National Water Model, based on WRF-Hydro, simulates current and future conditions on rivers and streams along points two miles apart across the contiguous United States. Along with an hourly analysis of current hydrologic conditions, the National Water Model generates three predictions: an hourly 0- to 15-hour short-range forecast, a daily 0- to 10-day medium-range forecast, and a daily 0- to 30-day long-range water resource forecast.The National Water Model predictions using WRF-Hydro offer a wide array of benefits for society. They will help local, state, and federal officials better manage reservoirs, improve navigation along major rivers, plan for droughts, anticipate water quality problems caused by lower flows, and monitor ecosystems for issues such as whether conditions are favorable for fish spawning. By providing a national view, this will also help the Federal Emergency Management Agency deploy resources more effectively in cases of simultaneous emergencies, such as a hurricane in the Gulf Coast and flooding in California."We've never had such a comprehensive system before," Gochis said. "In some ways, the value of this is a blank page yet to be written."A broad spectrum of observationsWRF-Hydro is a powerful forecasting system that incorporates advanced meteorological and streamflow observations, including data from nearly 8,000 U.S. Geological Survey streamflow gauges across the country. Using advanced mathematical techniques, the model then simulates current and future conditions for millions of points on every significant river, steam, tributary, and catchment in the United States.In time, scientists will add additional observations to the model, including snowpack conditions, lake and reservoir levels, subsurface flows, soil moisture, and land-atmosphere interactions such as evapotranspiration, the process by which water in soil, plants, and other land surfaces evaporates into the atmosphere.Scientists over the last year have demonstrated the accuracy of WRF-Hydro by comparing its simulations to observations of streamflow, snowpack, and other variables. They will continue to assess and expand the system as the National Water Model begins operational forecasts.NCAR scientists maintain and update the open-source code of WRF-Hydro, which is available to the academic community and others. WRF-Hydro is widely used by researchers, both to better understand water resources and floods in the United States and other countries such as Norway, Germany, Romania, Turkey, and Israel, and to project the possible impacts of climate change."At any point in time, forecasts from the new National Water Model have the potential to impact 300 million people," Gochis said. "What NOAA and its collaborator community are doing is trying to usher in a new era of bringing in better physics and better data into forecast models for improving situational awareness and hydrologic decision making."CollaboratorsBaron Advanced Meteorological Services Consortium of Universities for the Advancement of Hydrologic ScienceIsrael Hydrologic ServiceNational Center for Atmospheric ResearchNational Oceanic and Atmospheric AdministrationU.S. Geological SurveyFundersNational Science FoundationNational Aeronautics and Space AdministrationNational Oceanic and Atmospheric Administration

RAL Seminar - Doug Olsen & Mark Askelson

Tuesday, August 16, 2016
10am - 11am
FL 2 - Room 1001

Doug Olsen and Mark Askelson - University of North Dakota

Unmanned Aerial Systems at UND:

Center of Excellens, FAA Test Site and Atmospheric Research

3D-printed weather stations fill gaps in developing world

BOULDER — Scientists have successfully installed the first wave of low-cost weather stations that are designed to provide critically needed information to farmers and other residents in developing countries. The stations are built largely with 3D-printed parts that can be easily replaced if they wear out in the field. They were created by weather experts at the National Center for Atmospheric Research (NCAR) and its managing entity, the University Corporation for Atmospheric Research (UCAR). The first five stations, newly installed in Zambia, are beginning to transmit information about temperature, rainfall, winds, and other weather parameters. These measurements and the resulting forecasts can provide weather information for local subsistence farmers deciding when to plant and fertilize crops. They can also alert communities about floods and other potential disasters. A newly installed weather station at the Salvation Army's College of Biomedical Sciences in Chikankata, Zambia. The sensor on the left (with the funnel) is a specially designed tipping bucket rain gauge; the vertical, vented cylinder on the vertical arm of the station is a radiation shield containing temperature, humidity, and pressure sensors; and the horizontal cylinder protruding out the back contains a single-board computer. A wind vane (left), solar light sensor (middle), and three-cup wind anemometer (right) are mounted on the upper arm.  The station is powered by a single solar panel and a backup battery. (©UCAR. Photo by Martin Steinson. This image is freely available for media & nonprofit use.) "It’s a major opportunity to provide weather information that farmers have never had before," said NCAR scientist Paul Kucera, one of the project leaders. "This can literally make the difference when it comes to being able to feed their families." The scientists will next explore the need for low-cost weather stations in other developing countries. The project is funded by the U.S. Agency for International Development's Office of Foreign Disaster Assistance and the U.S. National Weather Service. “The bottom line is that 3D-printing will help to save lives,” said Sezin Tokar, a hydrometeorologist with U.S. AID. “Not only can they provide countries with the ability to more accurately monitor for weather-related disasters, the data they produce can also help reduce the economic impact of disasters.” Lack of observations Like many developing countries, Zambia does not have detailed forecasts, partly because weather stations are scarce. The density of stations in Africa is eight times lower than recommended by the World Meteorological Organization. Building out a network can be prohibitively expensive, with a single commercial weather station often costing $10,000 to $20,000, plus ongoing funding for maintenance and replacing worn-out parts. To fill this need, UCAR and NCAR scientists have worked for years to come up with a weather station that is cheap and easy to fix, and can be adapted to the needs of the host country. The resulting stations are constructed out of plastic parts that are custom designed and can be run off a 3D printer, along with off-the-shelf sensors and a basic, credit card-sized computer developed for schoolchildren. Total cost: about $300 per station. Best of all, the host country can easily print replacement parts. "If you want a different kind of wind direction gauge or anemometer, or you just need to replace a broken part, you can just print it out yourself," said project co-lead Martin Steinson of UCAR. "Our role is to make this as accessible as possible. This is entirely conceived as an open-source project." Building out a network Working with the Zambian Meteorological Department and other agencies, Kucera and Steinson installed the first stations earlier this year—three next to radio stations that will broadcast the information to local communities, one by a rural hospital, and one by the headquarters of the meteorological department. The meteorological office will take over the project later this year, with a goal of building out a network of 100 weather stations across Zambia. They will also have the 3D printers, materials, and training to maintain or upgrade the network. The weather station measurements are accessible to local meteorologists and also transmitted over wireless networks in real time to NCAR. After all the weather stations have been installed, scientists will develop a system of one- to three-day regional forecasts for Zambia using the NCAR-based Weather Research and Forecast (WRF) computer model. The forecasts, in addition to helping farmers and other residents, can also alert the country to the threat of impending floods or other weather-related disasters. The system will ultimately be transferred to the Zambian Meteorological Department to run the forecasts. "The objective of the project is to transfer the technology so this will be run by Zambia," Kucera said. Once the technology has been established in Zambia, Kucera and Steinson will turn to other nations that need additional weather stations, such as in Africa or the Caribbean. In addition to improving local forecasts, the additional observations can eventually make a difference for forecasts globally because computer models everywhere will have additional information about the atmosphere. "We’re hearing a lot of interest in using this technology in other countries," Kucera said. "It’s really quite a return on investment." Writer:David Hosansky, Manager of Media Relations

7th NCEP Ensemble Users Workshop

Jun 13-15, 2016 | at NCWCP 5830 University Research Ct. College Park, Maryland

Bias-adjustment of RCM simulations: from the synoptic to the catchment scale

Regional climate simulations can show large departures from observations, usually termed model biases. To deal with these biases, impact modelers such as hydrologists commonly resort to bias-adjustment methods, which do not account for the origins of biases in climate models and instead perform empirical adjustments.

Potential Zika virus risk estimated for 50 U.S. cities

BOULDER – Key factors that can combine to produce a Zika virus outbreak are expected to be present in a number of U.S. cities during peak summer months, new research shows.The Aedes aegypti mosquito, which is spreading the virus in much of Latin America and the Caribbean, will likely be increasingly abundant across much of the southern and eastern United States as the weather warms, according to a new study led by mosquito and disease experts at the National Center for Atmospheric Research (NCAR).Summertime weather conditions are favorable for populations of the mosquito along the East Coast as far north as New York City and across the southern tier of the country as far west as Phoenix and Los Angeles, according to computer simulations conceived and run by researchers at NCAR and the NASA Marshall Space Flight Center.Spring and fall conditions can support low to moderate populations of the Aedes aegypti mosquito in more southern regions of its U.S. range. Wintertime weather is too cold for the species outside southern Florida and southern Texas, the study found.By analyzing travel patterns from countries and territories with Zika outbreaks, the research team further concluded that cities in southern Florida and impoverished areas in southern Texas may be particularly vulnerable to local virus transmission.Many U.S. cities face potential risk in summer of low, moderate, or high populations of the mosquito species that transmits Zika virus (colored circles). The mosquito has been observed in parts of the United States (shaded portion of map) and can establish populations in additional cities because of favorable summertime meteorological conditions. In addition, Zika risk may be elevated in cities with more air travelers arriving from Latin America and the Caribbean (larger circles). For a high-resolution map, click here or on the image. (Image based on data mapped by Olga Wilhelmi, NCAR GIS program. This image is freely available for media & nonprofit use.) "This research can help us anticipate the timing and location of possible Zika virus outbreaks in certain U.S. cities,” said NCAR scientist Andrew Monaghan, the lead author of the study. “While there is much we still don’t know about the dynamics of Zika virus transmission, understanding where the Aedes aegypti mosquito can survive in the U.S. and how its abundance fluctuates seasonally may help guide mosquito control efforts and public health preparedness.”“Even if the virus is transmitted here in the continental U.S., a quick response can reduce its impact,” added NCAR scientist Mary Hayden, a medical anthropologist and co-author of the study.Although the study does not include a specific prediction for this year, the authors note that long-range forecasts for this summer point to a 40–45 percent chance of warmer-than-average temperatures over most of the continental United States. Monaghan said this could lead to increased suitability for Aedes aegypti in much of the South and East, although above-normal temperatures would be less favorable for the species in the hottest regions of Texas, Arizona, and California.Monaghan stressed that, even if Zika establishes a toehold in the mainland United States, it is unlikely to spread as widely as in Latin America and the Caribbean. This is partly because a higher percentage of Americans live and work in air-conditioned and largely sealed homes and offices.The study is being published today in the peer-reviewed journal PLOS Currents Outbreaks. It was funded by the National Institutes of Health, NASA, and the National Science Foundation, which is NCAR’s sponsor. It was co-authored by scientists at NASA, North Carolina State University, Maricopa County Environmental Services Vector Control Division, University of Arizona, and Durham University.Spreading rapidlyFirst identified in Uganda in 1947, the Zika virus has moved through tropical regions of the world over the past decade. It was introduced into Brazil last year and spread explosively across Latin America and the Caribbean, with more than 20 countries now facing pandemics.About 80 percent of infected people do not have significant symptoms, and most of the rest suffer relatively mild flu- or cold-like symptoms that generally clear up in about a week. However, scientists are investigating correlations between contracting the disease during pregnancy and microcephaly, a rare birth defect characterized by an abormally small head and brain damage.To determine the potential risk in the mainland United States, the research team ran two computer models that simulated the effect of meteorological conditions on a mosquito’s entire lifecycle (egg, larval, pupal, and adult stages) in 50 cities in or near the known range of the species. Monaghan and several team members have studied Aedes aegypti for years because it also carries the viruses that cause dengue and chikungunya.Generally, the mosquitoes need warm and relatively stable temperatures, as well as water-filled containers such as buckets, barrels, or tires, for their eggs to hatch. Once a mosquito bites an infected person, it also needs to live long enough – probably a week or more, depending on ambient temperatures – for the virus to travel from the mosquito's mid-gut to its salivary glands. Once in the saliva, the virus can then be transmitted by the mosquito biting another person.The study results show that, as springtime weather warms, the potential abundance of the mosquito begins to increase in April in the Southeast and some Arizona cities. By June, nearly all of the 50 cities studied have the potential for at least low-to-moderate abundance, and most eastern cities are suitable for moderate-to-high abundance. Conditions become most suitable for mosquito populations in July, August, and September, although the peak times vary by city. Weather conditions in southern and western cities remain suitable as late as November.Even some cities where the Aedes aegypti mosquito has not been detected, such as St. Louis and Denver, have suitable midsummer weather conditions for the species if it were introduced via transport of used tires or by other human activities, according to the computer models.The researchers stressed that additional factors outside the scope of the study could affect populations of the species, such as mosquito control efforts, competition with other mosquito species, and the extent to which eggs can survive in borderline temperatures.The study noted that northern cities could become vulnerable if a related species of mosquito that is more tolerant of cold temperatures, Aedes albopictus, begins to carry the virus.This animation shows the varying extent to which meteorological conditions can favor populations of the Aedes aegypti mosquito, which transmits the Zika virus, in 50 U.S. cities throughout the year. Red dots represent high-abundance conditions, orange represents medium-to-high, yellow represents low-to-medium, and gray represents no significant mosquito population. (Animation based on data from Andrew Monaghan, NCAR. This image is freely available for media & nonprofit use.)Factoring in travel, povertyIn addition to looking at meteorological conditions, the researchers studied two other key variables that could influence the potential for Zika outbreaks: travel from Zika-affected areas and socioeconomic conditions in states that may face abundant mosquito populations.To analyze air travel, the team estimated the number of passengers arriving into U.S. cities on direct flights from airports in 22 Latin American countries and territories listed on the Centers for Disease Control and Prevention’s Zika travel advisory as of January 29.Cities that had both high potential numbers of Aedes aegypti and a large volume of air travelers included Miami, Houston, and Orlando. Since the scientists were able to obtain passenger numbers for direct flights only, they could not estimate the number of passengers continuing on to smaller cities. They noted that the summertime peak in air travel coincides with the peak season in mosquito abundance.The study also estimated that nearly five times as many people cross the U.S.-Mexico border per month than arrive by air in all 50 cities. This could indicate a high potential for transmission in border areas from Texas to California, although the Zika virus has not been widely reported in northern Mexico.Those border areas, as well as other parts of the South where the mosquitoes are expected to be abundant, have a high percentage of households living below the poverty line, according to 2014 U.S. Census data analyzed by the research team. Lower-income residents can be more exposed to mosquito bites if they live in houses without air conditioning or have torn or missing screens that enable mosquitoes to enter their homes more easily. However, Aedes aegypti populations tend to thrive in densely populated urban areas, while some of the most impoverished areas are rural.“The results of this study are a step toward providing information to the broader scientific and public health communities on the highest risk areas for Zika emergence in the United States,” said Kacey Ernst, an epidemiologist at the University of Arizona and co-author of the study. “We hope that others will build on this work as more information becomes available. All areas with an environment suitable to the establishment of Aedes aegypti should be working to enhance surveillance strategies to monitor the Aedes aegypti populations and human populations for disease emergence.”“This research highlights the complex set of human and environmental factors that determine whether a mosquito-borne disease is carried from one area to another, and how severely it affects different human populations,” said Sarah Ruth, program director in the National Science Foundation’s Division of Atmospheric and Geospace Sciences. “By integrating information on weather, travel patterns, mosquito biology, and human behavior, the project team has improved our ability to forecast, deal with, and possibly even prevent future outbreaks of Zika and other serious diseases.”About the articleTitle: On the seasonal occurrence and abundance of the Zika virus vector mosquito Aedes aegypti in the contiguous United StatesAuthors: Andrew Monaghan, Cory Morin, Daniel Steinhoff, Olga Wilhelmi, Mary Hayden, Dale Quattrochi, Michael Reiskind, Alun Lloyd, Kirk Smith, Christopher Schmidt, Paige Scalf, and Kacey ErnstJournal: PLOS Currents Outbreaks

Pages

Subscribe to RAL