Tropical overshooting convection has a strong impact on both heat budget and moisture distributio... more Tropical overshooting convection has a strong impact on both heat budget and moisture distribution in the upper troposphere and lower stratosphere, and it can pose a great risk to aviation safety. Cloud-top height is one of the essential concerns of overshooting convection for both the climate system and the aviation weather forecast. The main purpose of our work is to verify the application of the machine learning method, taking the random forest (RF) model as an instance, in overshooting cloud-top height retrieval from Himawari-8 data. By using collocated CloudSat observations as a reference, we utilize several infrared indicators of Himawari-8 that are commonly recognized to relate to cloud-top height, along with some temporal and geographical parameters (latitude, month, satellite zenith angle, etc.), as predictors to construct and validate the model. Analysis of variable importance shows that the brightness temperature of 6.2 um acts as the dominant predictor, followed by satel...
We developed an entraining parcel approach that partitions parcel buoyancy into contributions fro... more We developed an entraining parcel approach that partitions parcel buoyancy into contributions from different processes (e.g., adiabatic cooling, condensation, freezing, and entrainment). Applying this method to research-quality radiosonde profiles provided by the Atmospheric Radiation Measurement (ARM) program at six sites, we evaluated how atmospheric thermodynamic conditions and entrainment influence various physical processes that determine the vertical buoyancy structure across different climate regimes as represented by these sites. The differences of morning buoyancy profiles between the deep convection (DC)/transition cases and shallow convection (SC)/nontransition cases were used to assess preconditions important for shallow-to-deep convection transition. Our results show that for continental sites such as the U.S. Southern Great Plains (SGP) and west-central Africa, surface conditions alone are enough to account for the buoyancy difference between DC and SC cases, although ...
Mike Waldon (DOI Everglades Program Team) gave a presentation on his research: “Near Zeroth Order... more Mike Waldon (DOI Everglades Program Team) gave a presentation on his research: “Near Zeroth Order Sulfate Disappearance Rate Estimated using Models of the Arthur R. Marshall Loxahatchee National Wildlife Refuge”. He described how the hydrology of the Loxahatchee area (aka WCA1) has been altered from a predominantly sheet-flow system to a riparian wetland, and that the water chemistry had been altered from a rainfall-fed system to one with elevated chloride, sulfate, and total P. He stated that the input of canal water was the primary source of sulfate contamination in the marsh interior. The rate of sulfate disappearance (reduction flux) was relatively constant (~15 g/m2/yr) and was not sulfate limited. The results of their efforts to model sulfate concentrations in the canals and the marsh suggested that a first order model required a 20-fold adjustment in the rate constant (the effective sulfate disappearance rate in m/yr) to fit data from the canals to the marsh interior, while a...
Purpose Village landscapes, which integrate small-scale agriculture with housing, forestry and a ... more Purpose Village landscapes, which integrate small-scale agriculture with housing, forestry and a host of other land use practices, cover more than 2×106 km2 across China. Village lands tend to be managed at very fine spatial scales (≤30 m), with managers altering soil fertility and even terrain by terracing, irrigation, fertilizing, and other land use practices. Under these conditions, accumulation of excess phosphorous in soils has become important contributor to eutrophication of surface waters across China’s densely populated village landscapes. The aim of this study was to investigate relationships between fine-scale patterns of agricultural management and soil total phosphorus (STP) within China’s village landscapes. Materials and methods First, China’s village landscapes
Barrier islands are dynamic environments because of their position along the marine–estuarine int... more Barrier islands are dynamic environments because of their position along the marine–estuarine interface. Geomorphology influences habitat distribution on barrier islands by regulating exposure to harsh abiotic conditions. Researchers have identified linkages between habitat and landscape position, such as elevation and distance from shore, yet these linkages have not been fully leveraged to develop predictive models. Our aim was to evaluate the performance of commonly used machine learning algorithms, including K-nearest neighbor, support vector machine, and random forest, for predicting barrier island habitats using landscape position for Dauphin Island, Alabama, USA. Landscape position predictors were extracted from topobathymetric data. Models were developed for three tidal zones: subtidal, intertidal, and supratidal/upland. We used a contemporary habitat map to identify landscape position linkages for habitats, such as beach, dune, woody vegetation, and marsh. Deterministic accu...
Tropical overshooting convection has a strong impact on both heat budget and moisture distributio... more Tropical overshooting convection has a strong impact on both heat budget and moisture distribution in the upper troposphere and lower stratosphere, and it can pose a great risk to aviation safety. Cloud-top height is one of the essential concerns of overshooting convection for both the climate system and the aviation weather forecast. The main purpose of our work is to verify the application of the machine learning method, taking the random forest (RF) model as an instance, in overshooting cloud-top height retrieval from Himawari-8 data. By using collocated CloudSat observations as a reference, we utilize several infrared indicators of Himawari-8 that are commonly recognized to relate to cloud-top height, along with some temporal and geographical parameters (latitude, month, satellite zenith angle, etc.), as predictors to construct and validate the model. Analysis of variable importance shows that the brightness temperature of 6.2 um acts as the dominant predictor, followed by satel...
We developed an entraining parcel approach that partitions parcel buoyancy into contributions fro... more We developed an entraining parcel approach that partitions parcel buoyancy into contributions from different processes (e.g., adiabatic cooling, condensation, freezing, and entrainment). Applying this method to research-quality radiosonde profiles provided by the Atmospheric Radiation Measurement (ARM) program at six sites, we evaluated how atmospheric thermodynamic conditions and entrainment influence various physical processes that determine the vertical buoyancy structure across different climate regimes as represented by these sites. The differences of morning buoyancy profiles between the deep convection (DC)/transition cases and shallow convection (SC)/nontransition cases were used to assess preconditions important for shallow-to-deep convection transition. Our results show that for continental sites such as the U.S. Southern Great Plains (SGP) and west-central Africa, surface conditions alone are enough to account for the buoyancy difference between DC and SC cases, although ...
Mike Waldon (DOI Everglades Program Team) gave a presentation on his research: “Near Zeroth Order... more Mike Waldon (DOI Everglades Program Team) gave a presentation on his research: “Near Zeroth Order Sulfate Disappearance Rate Estimated using Models of the Arthur R. Marshall Loxahatchee National Wildlife Refuge”. He described how the hydrology of the Loxahatchee area (aka WCA1) has been altered from a predominantly sheet-flow system to a riparian wetland, and that the water chemistry had been altered from a rainfall-fed system to one with elevated chloride, sulfate, and total P. He stated that the input of canal water was the primary source of sulfate contamination in the marsh interior. The rate of sulfate disappearance (reduction flux) was relatively constant (~15 g/m2/yr) and was not sulfate limited. The results of their efforts to model sulfate concentrations in the canals and the marsh suggested that a first order model required a 20-fold adjustment in the rate constant (the effective sulfate disappearance rate in m/yr) to fit data from the canals to the marsh interior, while a...
Purpose Village landscapes, which integrate small-scale agriculture with housing, forestry and a ... more Purpose Village landscapes, which integrate small-scale agriculture with housing, forestry and a host of other land use practices, cover more than 2×106 km2 across China. Village lands tend to be managed at very fine spatial scales (≤30 m), with managers altering soil fertility and even terrain by terracing, irrigation, fertilizing, and other land use practices. Under these conditions, accumulation of excess phosphorous in soils has become important contributor to eutrophication of surface waters across China’s densely populated village landscapes. The aim of this study was to investigate relationships between fine-scale patterns of agricultural management and soil total phosphorus (STP) within China’s village landscapes. Materials and methods First, China’s village landscapes
Barrier islands are dynamic environments because of their position along the marine–estuarine int... more Barrier islands are dynamic environments because of their position along the marine–estuarine interface. Geomorphology influences habitat distribution on barrier islands by regulating exposure to harsh abiotic conditions. Researchers have identified linkages between habitat and landscape position, such as elevation and distance from shore, yet these linkages have not been fully leveraged to develop predictive models. Our aim was to evaluate the performance of commonly used machine learning algorithms, including K-nearest neighbor, support vector machine, and random forest, for predicting barrier island habitats using landscape position for Dauphin Island, Alabama, USA. Landscape position predictors were extracted from topobathymetric data. Models were developed for three tidal zones: subtidal, intertidal, and supratidal/upland. We used a contemporary habitat map to identify landscape position linkages for habitats, such as beach, dune, woody vegetation, and marsh. Deterministic accu...
Uploads
Papers by Hongqing Wang