4,699 research outputs found

    Modeling the impact of land surface feedbacks on post landfall tropical cyclones

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    The land surface is an important component of numerical models. The land surface models are modules that control energy partitioning, compute surface exchange coefficients and form the only physical boundary in a regional scale numerical model. Thus, an accurate representation of land surface is critical to compute surface fluxes, represent the boundary layer evolution and affect changes in weather systems. Land surface can affect landfalling tropical cyclones in two ways: (i) when the cyclone is offshore and land can influence cyclones by introducing dry (or moist) air that can weaken (or strengthen) the organized convective structure of cyclones, and (ii) land can affect the evolution of cyclones post landfall by modifying the surface heat fluxes and introducing additional surface drag. In this dissertation, the hypothesis that improved representation of land surface conditions will improve the prediction of landfalling tropical cyclones is tested. To that effect, a comprehensive review of land surface effects on tropical cyclones was undertaken and an idealized study was conducted to study the impact of antecedent soil temperature on the sustenance/reintensification of tropical cyclones over land. Rainfall verification for cyclone events over the Atlantic Ocean was conducted and a comparison study between land models—GFDL Slab and Noah, also considers the sensitivity of tropical cyclone models to land surface parameterizations. The recent adoption of Noah land model with hydrology products in HWRF offers a unique opportunity to couple a river routing model to HWRF to provide streamflow estimations from the HWRF model and this dissertation has outlined techniques to real time predict streamflow for United States with HWRF forcing. Results from this dissertation research indicate antecedent land surface conditions can affect tropical cyclone evolution post landfall and high soil temperature and thermally diffusive soil texture of land surface are critical factors contributing to re-intensification/ sustenance of tropical cyclones. This idealized study, in addition to enabling improved understanding of the land surface effects on cyclones, has also led to a developmental effort to incorporate landfalling capability in the idealized framework of HWRF model and is available for use for the wider tropical cyclone community. The development of river routing coupled HWRF model could also be used in the operational mode to improve flooding and streamflow predictions and efforts are underway to integrate this new capability in HWRF. Study findings contribute to the understanding regarding the effects of land surface on landfalling cyclones and helps translate research products into HWRF’s operational framework for predicting tropical cyclones

    Towards the “Perfect” Weather Warning

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    This book is about making weather warnings more effective in saving lives, property, infrastructure and livelihoods, but the underlying theme of the book is partnership. The book represents the warning process as a pathway linking observations to weather forecasts to hazard forecasts to socio-economic impact forecasts to warning messages to the protective decision, via a set of five bridges that cross the divides between the relevant organisations and areas of expertise. Each bridge represents the communication, translation and interpretation of information as it passes from one area of expertise to another and ultimately to the decision maker, who may be a professional or a member of the public. The authors explore the partnerships upon which each bridge is built, assess the expertise and skills that each partner brings and the challenges of communication between them, and discuss the structures and methods of working that build effective partnerships. The book is ordered according to the “first mile” paradigm in which the decision maker comes first, and then the production chain through the warning and forecast to the observations is considered second. This approach emphasizes the importance of co-design and co-production throughout the warning process. The book is targeted at professionals and trainee professionals with a role in the warning chain, i.e. in weather services, emergency management agencies, disaster risk reduction agencies, risk management sections of infrastructure agencies. This is an open access book

    Proceedings of the XXVIIIth TELEMAC User Conference 18-19 October 2022

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    Hydrodynamic

    Earth resources: A continuing bibliography with indexes (issue 58)

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    This bibliography lists 500 reports, articles, and other documents introduced into the NASA scientific and technical information system between April 1 and June 30, 1988. Emphasis is placed on the use of remote sensing and geophysical instrumentation in spacecraft and aircraft to survey and inventory natural resources and urban areas. Subject matter is grouped according to agriculture and forestry, environmental changes and cultural resources, geodesy and cartography, geology and mineral resources, hydrology and water management, data processing and distribution systems, instrumentation and sensors, and economic analysis

    10th HyMeX Workshop

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    Evapotranspiration from Green Infrastructure: Benefit, Measurement, and Simulation

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    Green infrastructure (GI) is a common solution for stormwater management in an urban environment, with attached environmental benefits like flood control, urban heat island relief, adaptations to climate change, biodiversity protection, air pollution reduction, and food production. Evapotranspiration (ET) controls the GI’s hydrologic performance and affects all related benefits. Essentially, ET constrains the turnover of moisture storage and determines the demand for supplemental irrigation and then the cost-effectiveness of a GI project. Considering the spatial heterogeneousness of an urban space and the GI’s multi-layer designs, the classic ET equations have challenges in representing the ET variations from GI units. The underperformance of the existing ET models is partly due to the lack of corresponding high-quality field observations for each GI type in various urban settings. This chapter, therefore, summarizes the current research progress and existing challenges regarding the benefit, measurement, and simulation of ET process from GI

    The Coastal Convective Interactions Experiment (CCIE): understanding the role of sea breezes for hailstorm hotspots in Eastern Australia

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    The coastal convective interactions experiment (CCIE's) integration of climatological analysis with an intensive field campaign has provided an opportunity for revealing some of the complexities surrounding thunderstorm hotpots in complex physical settings like SEQ. For the CCIE climatological analysis, a continuous 18-yr (July 1997 to June 2015) volumetric reflectivity radar dataset was sourced from the 1.9° S-band weather radar located at Marburg, 50 km west of Brisbane. A cell-based analysis of this archive was performed using a MATLAB implementation of the identification, tracking, and selected analysis algorithms from the Weather Decision Support System-Integrated Information (WDSS-II). The 10-min interval of the Marburg radar volumes creates significant spatial discontinuities between MESH grids from an individual thunderstorm. A preliminary analysis indicates a strong relationship between the presence of the sea breeze and the Boonah hailstorm hotspot, but further analysis is needed to isolate the additional influence of synoptic and topographic drivers. Furthermore, fine-scale field observations of the sea-breeze?thunderstorm interaction events have begun to shed some light on the meteorology of thunderstorm hotspots in South East Queensland (SEQ)

    Land Use Effects On Energy And Water Balance-developing A Land Use Adapted Drought Index

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    Climate change is expected to increase the frequency, intensity and duration of droughts in all parts of the United States (US). Snow packs are disappearing earlier in the spring and summer, with reduced stream-flow. Lower reservoir levels, higher temperatures, and greater precipitation variability have been observed. Drought events in the US have threatened drinking water supplies for communities in Maryland and Chesapeake Bay as observed in 2001 through September 2002; Lake Mead in Las Vegas in 2000 through 2004; Peace River and Lake Okeechobee in South Florida in 2006; and Lake Lanier in Atlanta, Georgia in 2007. ENSO influences the climate of Florida; where El Niño years tend to be cooler and wetter, while La Niña years tend to be warmer and drier than normal in the fall through the spring, with the strongest effect in the winter. Both prolonged heavy rainfall and drought potentially have impacts on land uses and many aspects of Florida\u27s economy and quality of life. Drought indices could integrate various hydrological and meteorological parameters and quantify climate anomalies in terms of intensity, duration, and spatial extent, thus making it easier to communicate information to diverse users. Hence, understanding local ENSO patterns on regional scales and developing a new land use drought index in Florida are critical in agriculture and water resources planning and managements. Current drought indices have limitations and drawbacks such as calculation using climate data from meteorological stations, which are point measurements. In addition, weather stations are scarce in remote areas and are not uniformly distributed. Currently used drought indices like the iv PDSI and the Standardized Precipitation Index (SPI) could not fully demonstrate the land use effects. Other limitations include no single index that addresses universal drought impact. Hence, there is a renewed interest to develop a new “Regional Land Use Drought Index (RLDI) that could be applied for various land use areas and serve for short term water resources planning. In this study, the first and second research topics investigated water and energy budgets on the specific and important land use areas (urban, forest, agriculture and lake) in the State of Florida by using the North American Regional Reanalysis (NARR) reanalysis data. NARR data were used to understand how drought events, EI Niño, La Niña, and seasonal and inter-annual variations in climatic variables affect the hydrologic and energy cycle over different land use areas. The results showed that the NARR data could provide valuable, independent analysis of the water and energy budgets for various land uses in Florida. Finally, the high resolution land use (32km×32km) adapted drought indices were developed based on the NARR data from 1979 to 2002. The new regional land use drought indices were developed from normalized Bowen ratio and the results showed that they could reflect not only the level of severity in drought events resulting from land use effects, but also La Niña driven drought impacts
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