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Alan K Betts - One of the best experts on this subject based on the ideXlab platform.
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revisiting Hydrometeorology using cloud and climate observations
Journal of Hydrometeorology, 2017Co-Authors: Alan K Betts, Ahmed B Tawfik, R L DesjardinsAbstract:AbstractThis paper uses 620 station years of hourly Canadian Prairie climate data to analyze the coupling of monthly near-surface climate with opaque cloud, a surrogate for radiation, and precipitation anomalies. While the cloud–climate coupling is strong, precipitation anomalies impact monthly climate for as long as 5 months. The April climate has memory of precipitation anomalies back to freeze-up in November, mostly stored in the snowpack. The summer climate has memory of precipitation anomalies back to the beginning of snowmelt in March. In the warm season, mean temperature is strongly correlated to opaque cloud anomalies, but only weakly to precipitation anomalies. Mixing ratio anomalies are correlated to precipitation, but only weakly to cloud. The diurnal cycle of mixing ratio shifts upward with increasing precipitation anomalies. Positive precipitation anomalies are coupled to a lower afternoon lifting condensation level and a higher afternoon equivalent potential temperature; both favor increased...
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comparison of river basin Hydrometeorology in era interim and era 40 reanalyses with observations
Journal of Geophysical Research, 2009Co-Authors: Alan K Betts, Martin Kohler, Yuanchong ZhangAbstract:[1] The changes between the ERA-40 and ERA-Interim in the seasonal cycle of primarily temperature, precipitation and evaporation, the surface radiation budget, and the cloud fields are evaluated over three river basins, the Amazon, Mississippi, and Mackenzie, for the period 1990–2001, using a variety of surface observational data sets and the International Satellite Cloud Climatology Project data. In ERA-Interim over the Amazon, the unrealistic interannual drift of precipitation has been reduced, and annual precipitation is largely unbiased, although the seasonal amplitude of precipitation remains too small. However, ERA-Interim has a large cold 2-m temperature bias. The clear-sky surface shortwave flux in ERA-Interim is lower than that in ERA-40 and closer to observations. Low cloud cover has increased dramatically in ERA-Interim, and total reflective cloud cover has a larger positive bias in comparison with observations. The ratio of the precipitation heating of the atmosphere to the surface shortwave cloud forcing is much higher in the observations than that in both reanalyses. The diurnal cycle of precipitation has improved somewhat with the removal of a spurious early morning peak. For the Mississippi and Mackenzie river basins, the spin-up of precipitation in 24-h forecasts has been greatly reduced. Temperature biases are small in both reanalyses, but summer precipitation and evaporation exceed observational estimates. For the Mississippi river basin, reflective cloud cover in ERA-Interim has increased in winter and decreased in summer compared with that in ERA-40, giving a closer fit to the observations in both seasons. For the Mackenzie river basin, similar reflective cloud changes in ERA-Interim improve the fit to the observations in summer but not in winter.
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Hydrometeorology of the amazon in era 40
Journal of Hydrometeorology, 2005Co-Authors: Alan K Betts, John H Ball, Pedro Viterbo, Aiguo Dai, Jose A MarengoAbstract:The Hydrometeorology of the Amazon basin in the ERA-40 reanalysis for 1958–2001 is compared with observations of precipitation, temperature, and streamflow. After 1979, the reanalysis over the Amazon has a small cool bias of the order of 0.35 K, and a small low bias of precipitation of the order of 0.3 mm day 1 . In the early years (1958–72), there is a large upward drift in reanalysis precipitation and runoff associated with an upward drift in the atmospheric water vapor in the analysis, and a somewhat smaller downward drift of temperature as precipitation increases. In the presatellite data, there are inhomogeneities in the radiosonde and surface synoptic data, and there were problems with the variational analysis of humidity once satellite radiances were introduced. Approximate bias corrections can be made for precipitation and runoff on an annual basis, but this also removes some of the interannual variability. The reanalysis runoff–precipitation relationship is similar to the observed streamflow–precipitation relation, on an annual water-year basis. Compared to observations, ERA-40 precipitation for the Amazon is low by about 1.3 mm day 1 in the rainy season, and high by a smaller amount in the dry season. The precipitation bias produces a temperature bias in ERA-40 of the opposite sign on the annual time scale. The reanalysis has a small cold temperature bias after 1967, but on an annual time scale it reproduces the interannual variability of the observations. Although the biases in temperature and precipitation in recent decades are small, the difficulties with the analysis of atmospheric water vapor lead to large uncertainty in long-term trends of the water cycle.
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understanding Hydrometeorology using global models
Bulletin of the American Meteorological Society, 2004Co-Authors: Alan K BettsAbstract:The land surface coupling, a crucial element of the climate system, is explored in the recent 40-yr European Centre for Medium–Range Forecasts (ECMWF) reanalysis (ERA-40) model. In seasonal forecasts for the Northern Hemisphere summer, initialized with idealized soil moisture fields, the ERA-40 model has a large evaporation–precipitation feedback over the continents, and the memory of initial soil moisture is longest at high northern latitudes. Thirty years of hourly data from the ERA-40 reanalysis are averaged over the Madeira, Red–Arkansas, and Athabasca River basins. Although the model fully resolves the diurnal cycle and has an interactive prognostic cloud field, the transitions in the boundary layer climate over land can be mapped with remarkable precision by the daily mean state and daily flux averages. The coupling to cloud processes plays an essential role in the surface and boundary layer equilibrium. Soil moisture, cloud base, cloud cover, radiation fields, and evaporative fraction are coupled q...
Jose A Marengo - One of the best experts on this subject based on the ideXlab platform.
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long term trends and cycles in the Hydrometeorology of the amazon basin since the late 1920s
Hydrological Processes, 2009Co-Authors: Jose A MarengoAbstract:Rainfall and river indices for both the northern and southern Amazon were used to identify and explore long-term climate variability on the region. From a statistical analysis of the hydrometeorological series, it is concluded that no systematic unidirectional long-term trends towards drier or wetter conditions have been identified since the 1920s. The rainfall and river series showing variability at inter-annual scales linked to El Nino Southern Oscillation was detected in rainfall in the northern Amazon. It has a low-frequency variability with a peak at − 30 years identified in both rainfall and river series in the Amazon. The presence of cycles rather than a trend is characteristic of rainfall in the Amazon. These cycles are real indicators of decadal and multi-decadal variations in hydrology for both sides of the basin. Sea-level pressure (SLP) gradients between tropics and sub topics were explored in order to explain variability in the Hydrometeorology of the basin. Sea surface temperature (SST) gradients inside the tropical Atlantic and between the tropical Atlantic and the sub-tropical Atlantic have been assessed in the context of changes in rainfall in the Amazon, as compared to northern Argentina. Trends in SSTs in the subtropical Atlantic are linked to changes in rainfall and circulation in northern Argentina, and they seem to be related to multi-decadal variations of rainfall in the Amazon. Copyright © 2009 John Wiley & Sons, Ltd.
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Hydrometeorology of the amazon in era 40
Journal of Hydrometeorology, 2005Co-Authors: Alan K Betts, John H Ball, Pedro Viterbo, Aiguo Dai, Jose A MarengoAbstract:The Hydrometeorology of the Amazon basin in the ERA-40 reanalysis for 1958–2001 is compared with observations of precipitation, temperature, and streamflow. After 1979, the reanalysis over the Amazon has a small cool bias of the order of 0.35 K, and a small low bias of precipitation of the order of 0.3 mm day 1 . In the early years (1958–72), there is a large upward drift in reanalysis precipitation and runoff associated with an upward drift in the atmospheric water vapor in the analysis, and a somewhat smaller downward drift of temperature as precipitation increases. In the presatellite data, there are inhomogeneities in the radiosonde and surface synoptic data, and there were problems with the variational analysis of humidity once satellite radiances were introduced. Approximate bias corrections can be made for precipitation and runoff on an annual basis, but this also removes some of the interannual variability. The reanalysis runoff–precipitation relationship is similar to the observed streamflow–precipitation relation, on an annual water-year basis. Compared to observations, ERA-40 precipitation for the Amazon is low by about 1.3 mm day 1 in the rainy season, and high by a smaller amount in the dry season. The precipitation bias produces a temperature bias in ERA-40 of the opposite sign on the annual time scale. The reanalysis has a small cold temperature bias after 1967, but on an annual time scale it reproduces the interannual variability of the observations. Although the biases in temperature and precipitation in recent decades are small, the difficulties with the analysis of atmospheric water vapor lead to large uncertainty in long-term trends of the water cycle.
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advancing global and continental scale Hydrometeorology contributions of gewex Hydrometeorology panel
Bulletin of the American Meteorological Society, 2004Co-Authors: R G Lawford, Ronald E Stewart, John O Roads, H J Isemer, Michael J Manton, Jose A Marengo, Tetsuzo Yasunari, S Benedict, Toshio Koike, S WilliamsAbstract:he GHP* (refer to appendix for acronym expan- sions) was formed in 1995 to coordinate the ac- tivities of the CSEs and related global initiatives. Many of the GHP activities had their roots in projects that began in the late 1980s. At that time the space agen-
James A Smith - One of the best experts on this subject based on the ideXlab platform.
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flash flooding in arid semiarid regions dissecting the Hydrometeorology and hydrology of the 19 august 2014 storm and flood hydroclimatology in arizona
Journal of Hydrometeorology, 2017Co-Authors: Long Yang, James A Smith, Mary Lynn Baeck, Efrat Morin, David C. GoodrichAbstract:AbstractThe hydroclimatology, Hydrometeorology, and hydrology of flash floods in the arid/semiarid southwestern United States are examined through empirical analyses of long-term, high-resolution rainfall and stream gauging observations, together with hydrological modeling analyses of the 19 August 2014 storm based on the Kinematic Runoff and Erosion Model (KINEROS2). The analyses presented here are centered on identifying the structure and evolution of flood-producing storms, as well as the interactions of space–time rainfall variability and basin characteristics in determining the upper-tail properties of rainfall and flood magnitudes over this region. This study focuses on four watersheds in Maricopa County, Arizona, with contrasting geomorphological properties. Flash floods over central Arizona are concentrated in both time and space, reflecting controls of the North American monsoon and complex terrain. Thunderstorm systems during the North American monsoon, as represented by the 19 August 2014 storm...
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the hydrology and Hydrometeorology of flooding in the delaware river basin
Journal of Hydrometeorology, 2010Co-Authors: James A Smith, Mary Lynn Baeck, Gabriele Villarini, Witold F KrajewskiAbstract:Abstract Extreme floods in the Delaware River basin are examined through analyses of a sequence of record and near-record floods during September 2004, April 2005, and June 2006. The three flood episodes reflect three principal flood-generating mechanisms in the eastern United States: tropical cyclones (September 2004); late winter–early spring extratropical systems (April 2005); and warm-season convective systems (June 2006). Extreme flooding in the Delaware River basin is the product of heavy rainfall and runoff from high-gradient portions of the watershed. Orographic precipitation mechanisms play a central role in the extreme flood climatology of the Delaware River basin and, more generally, for the eastern United States. Extreme flooding for the 2004–06 events was produced in large measure from forested portions of the watershed. Analyses of flood frequency based on annual flood peak observations from U.S. Geological Survey (USGS) stream gauging stations with “long” records illustrate the striking het...
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the regional hydrology of extreme floods in an urbanizing drainage basin
Journal of Hydrometeorology, 2002Co-Authors: James A Smith, Mary Lynn Baeck, Julia E Morrison, Paula Sturdevantrees, Daniel F Turnergillespie, Paul D BatesAbstract:Abstract The Charlotte, North Carolina, metropolitan area has experienced extensive urban and suburban growth since 1960. Five of the largest flood peaks in the 74-yr discharge record of Little Sugar Creek, which drains the central urban corridor of Charlotte, have occurred since August of 1995. A central objective of this study is to explain how these two observations are linked. To achieve this goal, a series of hypotheses of broad importance to the hydrology and Hydrometeorology behavior of extreme floods will be examined. These hypotheses concern the roles of 1) space–time variability of rainfall, 2) antecedent soil moisture, 3) expansion of impervious area, and 4) alterations of the drainage network for extreme floods in urbanizing drainage basins. The methodology used to examine these hypotheses centers on diagnostic studies of flood response for the five major flood events that have occurred since August of 1995. Diagnostic studies exploit the diverse range of extreme precipitation forcing for the ...
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the hydrology and Hydrometeorology of extreme floods in the great plains of eastern nebraska
Advances in Water Resources, 2001Co-Authors: Yu Zhang, James A Smith, Mary Lynn BaeckAbstract:Abstract The Great Plains of eastern Nebraska occupy a distinctive hydroclimatological niche, characterized by a high frequency of organized thunderstorm systems. A consequence of the hydroclimatology of these systems is a sharp seasonal peak in the regional flood frequency in late June. Pebble Creek and Maple Creek are adjacent drainage basins in the Great Plains of Nebraska with drainage areas of 528 and 1165 km 2 , respectively. The hydrometeorological and hydrologic controls of extreme floods are examined through analyses of a series of five major flood events that occurred in these catchments during the warm season of 1996. Particular attention is given to two storm systems. The 20–21 June flood event was produced by a series of tornadic supercell thunderstorms which tracked over Pebble Creek. The 4–5 August 1996 event, which resulted in record flood peaks in both Pebble Creek and Maple Creek, was produced by a system of multicellular thunderstorms. Analyses of the structure, motion and evolution of these two storm systems provide a conceptual framework for interpreting hydrometeorological controls of scale-dependent flood response. Hydrometeorological analyses are based on both volume scan WSR-88D reflectivity observations from the Omaha, Nebraska radar and composite reflectivity observations from the WSR-88D radar network. Analyses of composite reflectivity observations for the US east of the Rocky Mountains for the 4-year period from 1996 to 1999 are used to place the scale-dependent flood response of the Great Plains within a broader hydroclimatological context. Discharge data for Maple Creek and Pebble Creek, at 15 min time scale, serve as the basis for stream flow analyses. The striking contrasts in flood response between Maple Creek and Pebble Creek are related to contrasts in drainage network structure, infiltration properties and flood wave attenuation. The scale-dependent flood response of these catchments is analyzed in terms of the space-time variability of rainfall as viewed from the spatial perspective imposed by the drainage network of the basin.
Mary Lynn Baeck - One of the best experts on this subject based on the ideXlab platform.
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flash flooding in arid semiarid regions dissecting the Hydrometeorology and hydrology of the 19 august 2014 storm and flood hydroclimatology in arizona
Journal of Hydrometeorology, 2017Co-Authors: Long Yang, James A Smith, Mary Lynn Baeck, Efrat Morin, David C. GoodrichAbstract:AbstractThe hydroclimatology, Hydrometeorology, and hydrology of flash floods in the arid/semiarid southwestern United States are examined through empirical analyses of long-term, high-resolution rainfall and stream gauging observations, together with hydrological modeling analyses of the 19 August 2014 storm based on the Kinematic Runoff and Erosion Model (KINEROS2). The analyses presented here are centered on identifying the structure and evolution of flood-producing storms, as well as the interactions of space–time rainfall variability and basin characteristics in determining the upper-tail properties of rainfall and flood magnitudes over this region. This study focuses on four watersheds in Maricopa County, Arizona, with contrasting geomorphological properties. Flash floods over central Arizona are concentrated in both time and space, reflecting controls of the North American monsoon and complex terrain. Thunderstorm systems during the North American monsoon, as represented by the 19 August 2014 storm...
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the hydrology and Hydrometeorology of flooding in the delaware river basin
Journal of Hydrometeorology, 2010Co-Authors: James A Smith, Mary Lynn Baeck, Gabriele Villarini, Witold F KrajewskiAbstract:Abstract Extreme floods in the Delaware River basin are examined through analyses of a sequence of record and near-record floods during September 2004, April 2005, and June 2006. The three flood episodes reflect three principal flood-generating mechanisms in the eastern United States: tropical cyclones (September 2004); late winter–early spring extratropical systems (April 2005); and warm-season convective systems (June 2006). Extreme flooding in the Delaware River basin is the product of heavy rainfall and runoff from high-gradient portions of the watershed. Orographic precipitation mechanisms play a central role in the extreme flood climatology of the Delaware River basin and, more generally, for the eastern United States. Extreme flooding for the 2004–06 events was produced in large measure from forested portions of the watershed. Analyses of flood frequency based on annual flood peak observations from U.S. Geological Survey (USGS) stream gauging stations with “long” records illustrate the striking het...
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the regional hydrology of extreme floods in an urbanizing drainage basin
Journal of Hydrometeorology, 2002Co-Authors: James A Smith, Mary Lynn Baeck, Julia E Morrison, Paula Sturdevantrees, Daniel F Turnergillespie, Paul D BatesAbstract:Abstract The Charlotte, North Carolina, metropolitan area has experienced extensive urban and suburban growth since 1960. Five of the largest flood peaks in the 74-yr discharge record of Little Sugar Creek, which drains the central urban corridor of Charlotte, have occurred since August of 1995. A central objective of this study is to explain how these two observations are linked. To achieve this goal, a series of hypotheses of broad importance to the hydrology and Hydrometeorology behavior of extreme floods will be examined. These hypotheses concern the roles of 1) space–time variability of rainfall, 2) antecedent soil moisture, 3) expansion of impervious area, and 4) alterations of the drainage network for extreme floods in urbanizing drainage basins. The methodology used to examine these hypotheses centers on diagnostic studies of flood response for the five major flood events that have occurred since August of 1995. Diagnostic studies exploit the diverse range of extreme precipitation forcing for the ...
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the hydrology and Hydrometeorology of extreme floods in the great plains of eastern nebraska
Advances in Water Resources, 2001Co-Authors: Yu Zhang, James A Smith, Mary Lynn BaeckAbstract:Abstract The Great Plains of eastern Nebraska occupy a distinctive hydroclimatological niche, characterized by a high frequency of organized thunderstorm systems. A consequence of the hydroclimatology of these systems is a sharp seasonal peak in the regional flood frequency in late June. Pebble Creek and Maple Creek are adjacent drainage basins in the Great Plains of Nebraska with drainage areas of 528 and 1165 km 2 , respectively. The hydrometeorological and hydrologic controls of extreme floods are examined through analyses of a series of five major flood events that occurred in these catchments during the warm season of 1996. Particular attention is given to two storm systems. The 20–21 June flood event was produced by a series of tornadic supercell thunderstorms which tracked over Pebble Creek. The 4–5 August 1996 event, which resulted in record flood peaks in both Pebble Creek and Maple Creek, was produced by a system of multicellular thunderstorms. Analyses of the structure, motion and evolution of these two storm systems provide a conceptual framework for interpreting hydrometeorological controls of scale-dependent flood response. Hydrometeorological analyses are based on both volume scan WSR-88D reflectivity observations from the Omaha, Nebraska radar and composite reflectivity observations from the WSR-88D radar network. Analyses of composite reflectivity observations for the US east of the Rocky Mountains for the 4-year period from 1996 to 1999 are used to place the scale-dependent flood response of the Great Plains within a broader hydroclimatological context. Discharge data for Maple Creek and Pebble Creek, at 15 min time scale, serve as the basis for stream flow analyses. The striking contrasts in flood response between Maple Creek and Pebble Creek are related to contrasts in drainage network structure, infiltration properties and flood wave attenuation. The scale-dependent flood response of these catchments is analyzed in terms of the space-time variability of rainfall as viewed from the spatial perspective imposed by the drainage network of the basin.
Roni Avissar - One of the best experts on this subject based on the ideXlab platform.
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the Hydrometeorology of a deforested region of the amazon basin
Journal of Hydrometeorology, 2006Co-Authors: Renato Ramos Da Silva, Roni AvissarAbstract:Abstract A series of numerical simulations were performed to evaluate the capability of the Regional Atmospheric Modeling System (RAMS) to simulate the evolution of convection in a partly deforested region of the Amazon basin during the rainy season, and to elucidate some of the complex land–atmosphere interactions taking place in that region. Overall, it is demonstrated that RAMS can simulate properly the domain-average accumulated rainfall in Rondonia, Brazil, when provided with reliable initial profiles of atmospheric relative humidity and soil moisture. It is also capable of simulating important feedbacks involving the energy partition at the ground surface and the formation of convection. In general, more water in the soil and/or the atmosphere produces more rainfall. However, these conditions affect the onset of rainfall in opposite ways; while higher atmospheric relative humidity leads to early rainfall, higher soil moisture delays its formation. As compared to stratiform clouds, which tend to cove...
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impact of land use land cover change on regional Hydrometeorology in amazonia
Journal of Geophysical Research, 2002Co-Authors: Somnath Baidya Roy, Roni AvissarAbstract:[1] A high-resolution mesoscale model was used to investigate the impact of deforestation in Amazonia. Coherent mesoscale circulations were triggered by the surface heterogeneity; synoptic flow did not eliminate the circulations but advected them away from the location where they were generated. This was substantiated by satellite-derived cloud images. These circulations affected the transport of moisture and heat at the synoptic scale and can affect climate. Adequate parameterizations for these processes should be included in GCMs for more accurate climate simulations.
