scholarly journals Impacts of Aerosol Particle Size Distribution and Land Cover Land Use on Precipitation in a Coastal Urban Environment Using a Cloud-Resolving Mesoscale Model

2014 ◽  
Vol 2014 ◽  
pp. 1-17 ◽  
Author(s):  
Nathan Hosannah ◽  
Jorge E. Gonzalez
Keyword(s):  
Land Use ◽  
Particle Size ◽  
Land Cover ◽  
Aerosol Particle ◽  
Mesoscale Model ◽  
Cloud Condensation Nuclei ◽  
Atmospheric Modeling ◽  
Urban Environments ◽  
Precipitation Event ◽  
Aerosol Particle Size

Urban environments influence precipitation formation via response to dynamic effects, while aerosols are intrinsically necessary for rainfall formation; however, the partial contributions of each on urban coastal precipitation are not yet known. Here, the authors use aerosol particle size distributions derived from the NASA aerosol robotic network (AERONET) to estimate submicron cloud condensation nuclei (CCN) and supermicron CCN (GCCN) for ingestion in the regional atmospheric modeling system (RAMS). High resolution land data from the National Land Cover Database (NLCD) were assimilated into RAMS to provide modern land cover and land use (LCLU). The first two of eight total simulations were month long runs for July 2007, one with constant PSD values and the second with AERONET PSDs updated at times consistent with observations. The third and fourth runs mirrored the first two simulations for “No City” LCLU. Four more runs addressed a one-day precipitation event under City and No City LCLU, and two different PSD conditions. Results suggest that LCLU provides the dominant forcing for urban precipitation, affecting precipitation rates, rainfall amounts, and spatial precipitation patterns. PSD then acts to modify cloud physics. Also, precipitation forecasting was significantly improved under observed PSD and current LCLU conditions.

scholarly journals Evaluation of surface properties and atmospheric disturbances caused by post-dam alterations of land use/land cover

2014 ◽  
Vol 18 (9) ◽  
pp. 3711-3732 ◽  
Author(s):  
A. T. Woldemichael ◽  
F. Hossain ◽  
R. Pielke Sr.
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Energy Budget ◽  
Atmospheric Modeling ◽  
Dew Point ◽  
Precipitation Event ◽  
Land Use Land Cover ◽  
River Watershed ◽  
Precipitation Patterns ◽  
Lulc Changes

Abstract. This study adopted a differential land-use/land-cover (LULC) analysis to evaluate dam-triggered land–atmosphere interactions for a number of LULC scenarios. Two specific questions were addressed: (1) can dam-triggered LULC heterogeneities modify surface and energy budget, which, in turn, change regional convergence and precipitation patterns? (2) How extensive is the modification in surface moisture and energy budget altered by dam-triggered LULC changes occurring in different climate and terrain features? The Regional Atmospheric Modeling System (RAMS, version 6.0) was set up for two climatologically and topographically contrasting regions: the American River watershed (ARW), located in California, and the Owyhee River watershed (ORW), located in eastern Oregon. For the selected atmospheric river precipitation event of 29 December 1996 to 3 January 1997, simulations of three pre-defined LULC scenarios are performed. The definition of the scenarios are (1) the "control" scenario, representing the contemporary land use, (2) the "pre-dam" scenario, representing the natural landscape before the construction of the dams and (3) the "non-irrigation" scenario, representing the condition where previously irrigated landscape in the control is transformed to the nearby land-use type. Results indicated that the ARW energy and moisture fluxes were more extensively affected by dam-induced changes in LULC than the ORW. Both regions, however, displayed commonalities in the modification of land–atmosphere processes due to LULC changes, with the control–non-irrigation scenario creating more change than the control–pre-dam scenarios. These commonalities were: (1) the combination of a decrease in temperature (up to 0.15 °C) and an increase at dew point (up to 0.25 °C) was observed; (2) there was a larger fraction of energy partitioned to latent heat flux (up to 10 W m−2) that increased the amount of water vapor in the atmosphere and resulted in a larger convective available potential energy (CAPE); (3) low-level wind-flow variation was found to be responsible for pressure gradients that affected localized circulations, moisture advection and convergence. At some locations, an increase in wind speed up to 1.6 m s−1 maximum was observed; (4) there were also areas of well-developed vertical motions responsible for moisture transport from the surface to higher altitudes that enhanced precipitation patterns in the study regions.

scholarly journals Evaluation of surface properties and atmospheric disturbances caused by post-dam alterations of land-use/land-cover

2014 ◽  
Vol 11 (5) ◽  
pp. 5037-5075 ◽  
Author(s):  
A. T. Woldemichael ◽  
F. Hossain ◽  
R. Pielke
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Energy Budget ◽  
Convective Available Potential Energy ◽  
Atmospheric Modeling ◽  
Precipitation Event ◽  
Land Use Land Cover ◽  
River Watershed ◽  
Precipitation Patterns ◽  
Lulc Changes

Abstract. This study adopted a differential land-use/land-cover (LULC) analysis to evaluate dam-triggered land–atmosphere interactions for a number of LULC scenarios. Two specific questions were addressed: (1) can dam-triggered LULC heterogeneities modify surface and energy budget which, in turn, change regional convergence and precipitation patterns? and (2) how extensive is the modification in surface moisture and energy budget altered by dam-triggered LULC changes occurring in different climate and terrain features? The Regional Atmospheric Modeling System (RAMS, version 6.0) was set up for two climatologically and topographically contrasting regions: the American River Watershed (ARW) located in California and the Owyhee River Watershed (ORW) located in eastern Oregon. For the selected atmospheric river precipitation event of 29 December 1996 to 3 January 1997, simulations of three pre-defined LULC scenarios are performed. The definition of the scenarios are: (1) the control scenario representing the contemporary land-use, (2) the pre-dam scenario representing the natural landscape before the construction of the dams and (3) the non-irrigation scenario representing the condition where previously irrigated landscape in the control is transformed to the nearby land-use type. Results indicated that the ARW energy and moisture fluxes were more extensively affected by dam-induced changes in LULC than the ORW. Both regions, however, displayed commonalities in the modification of land–atmosphere processes due to LULC changes, with the control–non-irrigation scenario creating more change than the control–pre-dam scenarios. These commonalities were: (1) the combination of a decrease in temperature (up to 0.15 °C) and an increase in dewpoint (up to 0.25 °C) was observed, (2) there was a larger fraction of energy partitioned to latent heat flux (up to 10 W m−2) that increased the amount of water vapor to the atmosphere and resulted in a larger convective available potential energy (CAPE), (3) low level wind flow variation was found to be responsible for pressure gradients that affected localized circulations, moisture advection and convergence. At some locations, an increase in wind speed up to 1.6 m s−1 maximum was observed, (4) there were also areas of well developed vertical motions responsible for moisture transport from the surface to higher altitudes that enhanced precipitation patterns in the study regions.

scholarly journals Freezing Drizzle Formation in Stably Stratified Layer Clouds. Part II: The Role of Giant Nuclei and Aerosol Particle Size Distribution and Solubility

2005 ◽  
Vol 62 (7) ◽  
pp. 2037-2057 ◽  
Author(s):  
István Geresdi ◽  
Roy Rasmussen
Keyword(s):  
Size Distribution ◽  
Aerosol Particle ◽  
Mesoscale Model ◽  
Cloud Condensation Nuclei ◽  
Aerosol Particles ◽  
Size Distributions ◽  
Two Dimensional ◽  
Insoluble Particles ◽  
Aerosol Particle Size ◽  
Giant Nuclei

Abstract This paper investigates how the characteristics of aerosol particles (size distribution and solubility) as well as the presence of giant nuclei affect drizzle formation in stably stratified layer clouds. A new technique was developed to simulate the evolution of water drops from wet aerosol particles and implemented into a detailed microphysical model. The detailed microphysical model was incorporated into a one-dimensional parcel model and a two-dimensional version of the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5). Sensitivity experiments were performed with the parcel model using a constant updraft speed and with the two-dimensional model by simulating flow over a bell-shaped mountain. The results showed that 1) stably stratified clouds with weak updrafts (<10 cm s−1) can form drizzle relatively rapidly for maritime size distributions with any aerosol particle solubility, and for continental size distributions with highly insoluble particles due to the low number of activated cloud condensation nuclei (CCN) (<100 cm−3), 2) drizzle is suppressed in stably stratified clouds with weak updrafts (<10 cm s−1) for highly soluble urban and extreme urban size distributions, and 3) the presence of giant nuclei only has an effect on drizzle formation for the highly soluble continental aerosol size distributions.

The Research Possibility of Definition Mass Biological Nanoobjects Using Terahertz Laser Ablation Method

2009 ◽  
Vol 4 (3) ◽  
pp. 74-77
Author(s):  
Mikhail Vagin ◽  
Anton Unitsyn ◽  
Aleksandr Petrov ◽  
Aleksandr Kozlov ◽  
Sergey Malyshkin ◽  
...  
Keyword(s):  
Particle Size ◽  
Laser Ablation ◽  
Molecular Mass ◽  
Aerosol Particle ◽  
Free Electron ◽  
Free Electron Laser ◽  
Thz Radiation ◽  
Laser Ablation Method ◽  
Aerosol Particle Size ◽  
Mass Definition

Possibility of mass definition using terahertz laser ablation method for biological nanoobjects is researched. Diffusion spectrometer of aerosols was applied for measuring the size of dispersed products of terahertz laser ablation. Dependence of molecular mass from the aerosol particle size was obtained for fragments of DNA λ-hind. This work was carried out using THz radiation of free electron laser of Siberian center of photochemical researches.

Water Interaction with Mineral Dust Aerosol: Particle Size and Hygroscopic Properties of Dust

2018 ◽  
Vol 2 (4) ◽  
pp. 376-386 ◽  
Author(s):  
Sara Ibrahim ◽  
Manolis N. Romanias ◽  
Laurent Y. Alleman ◽  
Mohamad N. Zeineddine ◽  
Giasemi K. Angeli ◽  
...  
Keyword(s):  
Particle Size ◽  
Aerosol Particle ◽  
Mineral Dust ◽  
Dust Aerosol ◽  
Water Interaction ◽  
Hygroscopic Properties ◽  
Aerosol Particle Size
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