Search Results
You are looking at 1 - 10 of 11 items for :
- Author or Editor: Peter J. Lamb x
- Bulletin of the American Meteorological Society x
- Refine by Access: All Content x
A review on the development of climatic scenarios related to policy-oriented assessment of the impact of climatic variations is presented. It seeks to provide background information needed to evaluate the extent to which existing regional scenarios have utility in the above context, and whether and how such utility could be increased in the future. An appraisal of alternative approaches (both GCM and empirically based) that have been used to develop scenarios from the standpoints of their respective motivations, the methods employed, the acknowledged strengths (both present and potential) and weaknesses, the results obtained, and the credibility of those results is given. Types of research needed to make regional climatic scenarios of greater utility for the policy-oriented assessment of the impact of climatic variations are suggested.
A review on the development of climatic scenarios related to policy-oriented assessment of the impact of climatic variations is presented. It seeks to provide background information needed to evaluate the extent to which existing regional scenarios have utility in the above context, and whether and how such utility could be increased in the future. An appraisal of alternative approaches (both GCM and empirically based) that have been used to develop scenarios from the standpoints of their respective motivations, the methods employed, the acknowledged strengths (both present and potential) and weaknesses, the results obtained, and the credibility of those results is given. Types of research needed to make regional climatic scenarios of greater utility for the policy-oriented assessment of the impact of climatic variations are suggested.
This paper is derived from an address at an Illinois agricultural conference on the specified topic, “Are weather patterns changing?” It examines three contrasting perspectives on the weather and climate of the recent past and immediate future evident in the contemporary literature. One standpoint has interpreted recent weather extremes and climatic fluctuations as evidence that the earth is undergoing a larger-scale climatic change towards a cooler and more variable regime, while an alternative view considers these extremes and fluctuations to be part of normal climate. The third perspective results from the recent pronounced increase in atmospheric CO2, which may induce a warm climate change. The request to provide this address offered the additional opportunity of drawing agriculturalists' attention to the research their scientists, economists, and sociologists must perform before the adverse socioeconomic effects of weather and climate variability can be minimized. It was also stressed, however, that the atmospheric sciences will have to demonstrate credibility to win and retain this vital support required from other specialists.
This paper is derived from an address at an Illinois agricultural conference on the specified topic, “Are weather patterns changing?” It examines three contrasting perspectives on the weather and climate of the recent past and immediate future evident in the contemporary literature. One standpoint has interpreted recent weather extremes and climatic fluctuations as evidence that the earth is undergoing a larger-scale climatic change towards a cooler and more variable regime, while an alternative view considers these extremes and fluctuations to be part of normal climate. The third perspective results from the recent pronounced increase in atmospheric CO2, which may induce a warm climate change. The request to provide this address offered the additional opportunity of drawing agriculturalists' attention to the research their scientists, economists, and sociologists must perform before the adverse socioeconomic effects of weather and climate variability can be minimized. It was also stressed, however, that the atmospheric sciences will have to demonstrate credibility to win and retain this vital support required from other specialists.
Climate Research and Seasonal Forecasting for West Africans: Perceptions, Dissemination, and Use?
Perceptions, Dissemination, and Use?
Beginning in response to the disastrous drought of 1968–73, considerable research and monitoring have focused on the characteristics, causes, predictability, and impacts of West African Soudano–Sahel (10°–18°N) rainfall variability and drought. While these efforts have generated substantial information on a range of these topics, very little is known of the extent to which communities, activities at risk, and policy makers are aware of, have access to, or use such information. This situation has prevailed despite Glantz's provocative BAMS paper on the use and value of seasonal forecasts for the Sahel more than a quarter century ago. We now provide a systematic reevaluation of these issues based on questionnaire responses of 566 participants (in 13 communities) and 26 organizations in Burkina Faso, Mali, Niger, and Nigeria. The results reveal that rural inhabitants have limited access to climate information, with nongovernmental organizations (NGOs) being the most important source. Moreover, the pathways for information flow are generally weakly connected and informal. As a result, utilization of the results of climate research is very low to nonexistent, even by organizations responsible for managing the effects of climate variability. Similarly, few people have access to seasonal climate forecasts, although the vast majority expressed a willingness to use such information when it becomes available. Those respondents with access expressed great enthusiasm and satisfaction with seasonal forecasts. The results suggest that inhabitants of the Soudano–Sahel savanna are keen for changes that improve their ability to cope with climate variability, but the lack of information on alternative courses of action is a major constraint. Our study, thus, essentially leaves unchanged both Glantz's negative “tentative conclusion” and more positive “preliminary assessment” of 25 years ago. Specifically, while many of the infrastructural deficiencies and socioeconomic impediments remain, the great yearning for climate information by Soudano–Sahalians suggests that the time is finally ripe for fostering increased use. Therefore, a simple model for improved dissemination of climate research and seasonal climate forecast information is proposed. The tragedy is that a quarter century has passed since Glantz's clarion call.
Beginning in response to the disastrous drought of 1968–73, considerable research and monitoring have focused on the characteristics, causes, predictability, and impacts of West African Soudano–Sahel (10°–18°N) rainfall variability and drought. While these efforts have generated substantial information on a range of these topics, very little is known of the extent to which communities, activities at risk, and policy makers are aware of, have access to, or use such information. This situation has prevailed despite Glantz's provocative BAMS paper on the use and value of seasonal forecasts for the Sahel more than a quarter century ago. We now provide a systematic reevaluation of these issues based on questionnaire responses of 566 participants (in 13 communities) and 26 organizations in Burkina Faso, Mali, Niger, and Nigeria. The results reveal that rural inhabitants have limited access to climate information, with nongovernmental organizations (NGOs) being the most important source. Moreover, the pathways for information flow are generally weakly connected and informal. As a result, utilization of the results of climate research is very low to nonexistent, even by organizations responsible for managing the effects of climate variability. Similarly, few people have access to seasonal climate forecasts, although the vast majority expressed a willingness to use such information when it becomes available. Those respondents with access expressed great enthusiasm and satisfaction with seasonal forecasts. The results suggest that inhabitants of the Soudano–Sahel savanna are keen for changes that improve their ability to cope with climate variability, but the lack of information on alternative courses of action is a major constraint. Our study, thus, essentially leaves unchanged both Glantz's negative “tentative conclusion” and more positive “preliminary assessment” of 25 years ago. Specifically, while many of the infrastructural deficiencies and socioeconomic impediments remain, the great yearning for climate information by Soudano–Sahalians suggests that the time is finally ripe for fostering increased use. Therefore, a simple model for improved dissemination of climate research and seasonal climate forecast information is proposed. The tragedy is that a quarter century has passed since Glantz's clarion call.
Rainwatch
A Prototype GIS for Rainfall Monitoring in West Africa
This paper describes Rainwatch, a stand-alone, prototype Geographic Information System (GIS) application that automates and streamlines key aspects of rainfall data management, processing, and visualization for West Africa. Rainwatch is an interactive Map Objects Visual Basic application that permits the tracking of critical rainfall attributes beneficial to farmers. Using the simple-to-understand concept of cumulative rainfall plots, the program allows users to compare rainfall for any year against six percentile thresholds for a historical reference period (1965-2000). These thresholds separate dry, normal, and wet conditions. Users also can compare rainfall data between stations for a given season or between seasons for a particular station, and spatially interpolate rainfall for a single event, defined period, or an entire season. The system is dynamic and automatically updates all charts and tables as new data are added to the database. Thus, for this poor and drought-prone region, Rainwatch can help reduce delay in rainfall data processing, facilitate communication between data collection agencies, and generally make rainfall data more accessible and meaningful.
This paper describes Rainwatch, a stand-alone, prototype Geographic Information System (GIS) application that automates and streamlines key aspects of rainfall data management, processing, and visualization for West Africa. Rainwatch is an interactive Map Objects Visual Basic application that permits the tracking of critical rainfall attributes beneficial to farmers. Using the simple-to-understand concept of cumulative rainfall plots, the program allows users to compare rainfall for any year against six percentile thresholds for a historical reference period (1965-2000). These thresholds separate dry, normal, and wet conditions. Users also can compare rainfall data between stations for a given season or between seasons for a particular station, and spatially interpolate rainfall for a single event, defined period, or an entire season. The system is dynamic and automatically updates all charts and tables as new data are added to the database. Thus, for this poor and drought-prone region, Rainwatch can help reduce delay in rainfall data processing, facilitate communication between data collection agencies, and generally make rainfall data more accessible and meaningful.
The results of a pilot study to assess the feasibility of documenting the occurrence of jet contrails over the United States from high-resolution Defense Meteorological Satellite Program (DMSP) imagery are presented. They are strongly positive, suggesting that 1) contrails can be distinguished from natural cirrus on the imagery; 2) contrails are consistently identifiable; 3) contrails often occur in association with the natural cirrus and frequently spread; and 4) this spreading could extend the accompanying natural cirrus shield. The analyses also indicate that contrails tend to occur relatively frequently, that they more often cluster in groups than appear singly, and that they seem to show a preference for developing in (near) upper-tropospheric cold troughs (ridgelines). It is accordingly suggested that DMSP imagery can provide a basis for research into a contrail-cirrus-climate relationship.
The results of a pilot study to assess the feasibility of documenting the occurrence of jet contrails over the United States from high-resolution Defense Meteorological Satellite Program (DMSP) imagery are presented. They are strongly positive, suggesting that 1) contrails can be distinguished from natural cirrus on the imagery; 2) contrails are consistently identifiable; 3) contrails often occur in association with the natural cirrus and frequently spread; and 4) this spreading could extend the accompanying natural cirrus shield. The analyses also indicate that contrails tend to occur relatively frequently, that they more often cluster in groups than appear singly, and that they seem to show a preference for developing in (near) upper-tropospheric cold troughs (ridgelines). It is accordingly suggested that DMSP imagery can provide a basis for research into a contrail-cirrus-climate relationship.
An outline of the concept of the North Atlantic Oscillation (NAO), along with some of its history is presented. This is followed by a brief presentation of the results and implications of an encouraging new application of the NAO to a regional climate problem—the interannual variation of Moroccan winter-semester precipitation. That precipitation is shown to be inversely related to the concurrent state of the NAO, and the relationship is relatively strong by the standards of recent research into the mechanisms of tropical and subtropical precipitation fluctuations. It is suggested that the NAO is of particular significance for the important issue of the long-range prediction of Moroccan (and probably also Spanish, Portuguese, and Algerian) winter precipitation, and that further research on this subject is warranted. Several specific recommendations in the latter regard are made.
An outline of the concept of the North Atlantic Oscillation (NAO), along with some of its history is presented. This is followed by a brief presentation of the results and implications of an encouraging new application of the NAO to a regional climate problem—the interannual variation of Moroccan winter-semester precipitation. That precipitation is shown to be inversely related to the concurrent state of the NAO, and the relationship is relatively strong by the standards of recent research into the mechanisms of tropical and subtropical precipitation fluctuations. It is suggested that the NAO is of particular significance for the important issue of the long-range prediction of Moroccan (and probably also Spanish, Portuguese, and Algerian) winter precipitation, and that further research on this subject is warranted. Several specific recommendations in the latter regard are made.
In response to the need to improve climate services at the local, state, and regional levels, a national network of regional climate centers has developed. This paper provides the background to this development, and outlines the functions of the centers and identifies their benefits and beneficiaries. The centers are a source of climate expertise and maintain multifaceted interfaces with the public and private sectors. Each center a) performs services, including the management of the basic data for its region and the delivery of specialized products; b) conducts applied climate studies, including the monitoring of anomalous conditions and the promoting of regional research; and c) acquires and maintains specialized regional datasets. Examples are given for each function. The paper concludes by elaborating on the potential for focused, applied research to enhance the services provided by the regional centers. This includes reference to the current irrigation scheduling information service operated by the High Plains Regional Climate Center.
In response to the need to improve climate services at the local, state, and regional levels, a national network of regional climate centers has developed. This paper provides the background to this development, and outlines the functions of the centers and identifies their benefits and beneficiaries. The centers are a source of climate expertise and maintain multifaceted interfaces with the public and private sectors. Each center a) performs services, including the management of the basic data for its region and the delivery of specialized products; b) conducts applied climate studies, including the monitoring of anomalous conditions and the promoting of regional research; and c) acquires and maintains specialized regional datasets. Examples are given for each function. The paper concludes by elaborating on the potential for focused, applied research to enhance the services provided by the regional centers. This includes reference to the current irrigation scheduling information service operated by the High Plains Regional Climate Center.
The Canopy Horizontal Array Turbulence Study (CHATS) took place in spring 2007 and is the third in the series of Horizontal Array Turbulence Study (HATS) experiments. The HATS experiments have been instrumental in testing and developing subfilterscale (SFS) models for large-eddy simulation (LES) of planetary boundary layer (PBL) turbulence. The CHATS campaign took place in a deciduous walnut orchard near Dixon, California, and was designed to examine the impacts of vegetation on SFS turbulence. Measurements were collected both prior to and following leafout to capture the impact of leaves on the turbulence, stratification, and scalar source/sink distribution. CHATS utilized crosswind arrays of fast-response instrumentation to investigate the impact of the canopy-imposed distribution of momentum extraction and scalar sources on SFS transport of momentum, energy, and three scalars. To directly test and link with PBL parameterizations of canopy-modified turbulent exchange, CHATS also included a 30-m profile tower instrumented with turbulence instrumentation, fast and slow chemical sensors, aerosol samplers, and radiation instrumentation. A highresolution scanning backscatter lidar characterized the turbulence structure above and within the canopy; a scanning Doppler lidar, mini sodar/radio acoustic sounding system (RASS), and a new helicopter-observing platform provided details of the PBL-scale flow. Ultimately, the CHATS dataset will lead to improved parameterizations of energy and scalar transport to and from vegetation, which are a critical component of global and regional land, atmosphere, and chemical models. This manuscript presents an overview of the experiment, documents the regime sampled, and highlights some preliminary key findings.
The Canopy Horizontal Array Turbulence Study (CHATS) took place in spring 2007 and is the third in the series of Horizontal Array Turbulence Study (HATS) experiments. The HATS experiments have been instrumental in testing and developing subfilterscale (SFS) models for large-eddy simulation (LES) of planetary boundary layer (PBL) turbulence. The CHATS campaign took place in a deciduous walnut orchard near Dixon, California, and was designed to examine the impacts of vegetation on SFS turbulence. Measurements were collected both prior to and following leafout to capture the impact of leaves on the turbulence, stratification, and scalar source/sink distribution. CHATS utilized crosswind arrays of fast-response instrumentation to investigate the impact of the canopy-imposed distribution of momentum extraction and scalar sources on SFS transport of momentum, energy, and three scalars. To directly test and link with PBL parameterizations of canopy-modified turbulent exchange, CHATS also included a 30-m profile tower instrumented with turbulence instrumentation, fast and slow chemical sensors, aerosol samplers, and radiation instrumentation. A highresolution scanning backscatter lidar characterized the turbulence structure above and within the canopy; a scanning Doppler lidar, mini sodar/radio acoustic sounding system (RASS), and a new helicopter-observing platform provided details of the PBL-scale flow. Ultimately, the CHATS dataset will lead to improved parameterizations of energy and scalar transport to and from vegetation, which are a critical component of global and regional land, atmosphere, and chemical models. This manuscript presents an overview of the experiment, documents the regime sampled, and highlights some preliminary key findings.
