A5084137661- Meteorological Phenomena and Simulations
- Climate variability and models
- Wind and Air Flow Studies
- Atmospheric aerosols and clouds
- Atmospheric chemistry and aerosols
- Plant Water Relations and Carbon Dynamics
- Atmospheric and Environmental Gas Dynamics
- Fluid Dynamics and Turbulent Flows
- Cryospheric studies and observations
- Precipitation Measurement and Analysis
- Fire effects on ecosystems
- Hydrology and Drought Analysis
- Hydrological Forecasting Using AI
- Atmospheric Ozone and Climate
- Hydrology and Watershed Management Studies
- Landslides and related hazards
- Tropical and Extratropical Cyclones Research
- Aeolian processes and effects
- Air Quality and Health Impacts
- Fire dynamics and safety research
- Air Quality Monitoring and Forecasting
- Flood Risk Assessment and Management
- Computational Fluid Dynamics and Aerodynamics
- Solar Radiation and Photovoltaics
- Building Energy and Comfort Optimization
University of British Columbia
2014-2024
NOAA National Weather Service
1996
University of Wisconsin–Madison
1984-1994
Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)
1989
University of Washington
1973-1976
An equation is presented for wet-bulb temperature as a function of air and relative humidity at standard sea level pressure. It was found an empirical fit using gene-expression programming. This valid humidities between 5% 99% temperatures −20° 50°C, except situations having both low cold temperature. Over the range, errors in range from −1° to +0.65°C, with mean absolute error less than 0.3°C.
Abstract. Towards the end of June 2021, temperature records were broken by several degrees Celsius in cities Pacific Northwest areas US and Canada, leading to spikes sudden deaths sharp increases emergency calls hospital visits for heat-related illnesses. Here we present a multi-model, multi-method attribution analysis investigate extent which human-induced climate change has influenced probability intensity extreme heat waves this region. Based on observations, modelling classical...
Abstract. Towards the end of June 2021, temperature records were broken by several degrees Celsius in cities Pacific northwest areas U.S. and Canada, leading to spikes sudden deaths, sharp increases hospital visits for heat-related illnesses emergency calls. Here we present a multi-model, multi-method attribution analysis investigate what extent human-induced climate change has influenced probability intensity extreme heatwaves this region. Based on observations modeling, occurrence heatwave...
Abstract Two new postprocessing methods are proposed to reduce numerical weather prediction’s systematic and random errors. The first method consists of running a algorithm inspired by the Kalman filter (KF) through an ordered set analog forecasts rather than sequence in time (ANKF). forecast for given location is defined as past prediction that matches selected features current forecast. second weighted average observations verified when 10 best analogs were valid (AN). ANKF AN tested 10-m...
For the first time, long‐range transport of “Kosa” mineral aerosol from western China to southwestern British Columbia is documented. This late April 1998 event coincided with an episode photochemical smog and reduced dispersion in Lower Fraser Valley (LFV). Filter samples region show a massive injection crustal elements (Si, Fe, Al, Ca) concentrations Si approximately double those previously recorded. Ratios these Fe are shown be statistically similar ratios observed events Hawaii China. On...
A theory of the fluid entrainment rate into a turbulent, mixed layer across horizontal density interfaceis presented. By integrating turbulent kinetic energy equation over depth and assuming that turbulence dissipation rates are proportional to production rates, an is derived relatingthe potential change four major terms: 1) buoyant dueto heating at earths surface; 2) mechanical due wind shear 3) dynamic instabilities such as Kelvin-Helmholtz waves theversion interface; 4) losses internal...
A first-order turbulence theory is developed that describes eddy-like mixing. Named transilient after a Latin word meaning “leap across” this approach models the turbulent mixing between arrays of points separated in space. It differs from eddy-diffusivity it not restricted to transfer adjacent points. By explicitly including “large eddy” effects can handle across zero-gradient and counter-gradient situations such as found convective mixed layers. Applications might include pollutant...
This article examines the current practice of streamflow modelling, a field under development for over century. A sample wide range assessment and planning applications models is presented. The diversity in use these mirrored model complexity, modelling approaches ranging from empirical to physically based lumped fully distributed are described with examples. Predictions derived hydrological subject many sources error; discussed along methods error minimization or anticipation. Model...
Abstract This study evaluates the grid-length dependency of Weather Research and Forecasting (WRF) Model precipitation performance for two cases in Southern Great Plains United States. The aim is to investigate ability different cumulus microphysics parameterization schemes represent processes throughout transition between parameterized resolved convective scales (e.g., gray zone). include following: 1) a mesoscale system causing intense local precipitation, 2) frontal passage with light but...
Abstract Many statistical downscaling methods require observational inputs and expert knowledge thus cannot be generalized well across different regions. Convolutional neural networks (CNNs) are deep-learning models that have generalization abilities for various applications. In this research, we modify UNet, a semantic-segmentation CNN, apply it to the of daily maximum/minimum 2-m temperature (TMAX/TMIN) over western continental United States from 0.25° 4-km grid spacings. We select...
Abstract Statistical downscaling (SD) derives localized information from larger-scale numerical models. Convolutional neural networks (CNNs) have learning and generalization abilities that can enhance the of gridded data (Part I this study experimented with 2-m temperature). In research, we adapt a semantic-segmentation CNN, called UNet, to daily precipitation in western North America, low resolution (LR) 0.25° high (HR) 4-km grid spacings. We select LR precipitation, HR climatology,...
Not all cumulus clouds can vent mixed-layer air into the free atmosphere. Therefore, three subtypes of fair-weather are identified based on nature their interaction with mixed layer: forced, active and passive clouds. Forced clouds, visible tracers within tops some thermals, totally embedded layer. Active reach above level convection responsible for inhibiting growth venting pollutants from Passive decaying remnants formerly disconnected
Penetrative convection is modeled by a series of idealized disturbances at the base an atmospheric temperature inversion. Internal gravity waves excited in inversion are theoretically found to drain away fraction initial energy disturbances. The portion lost upward significant when weak. Vertical fluxes due internal mathematically described using wave group approaches.
A mathematical model to describe the height changes and other characteristics of an inversion base under influence surface convection general subsidence is developed. Inversion interface dynamics entrainment rates are formulated based on unstable boundary layer environment well-organized, plume-like, penetrative convection. The use scaling velocities in describing leads a natural inclusion relevant parameters associated with inversions into this model. It found that does accurately predict...
Abstract This study evaluates the sensitivity of wind turbine hub-height speed forecasts to planetary boundary layer (PBL) scheme, grid length, and initial condition selection in Weather Research Forecasting (WRF) Model over complex terrain. Eight PBL schemes available for WRF-ARW dynamical core were tested with conditions sources from North American Mesoscale (NAM) model Global Forecast System (GFS) produce short-term forecasts. The largest improvements forecast accuracy primarily depended...
The Kalman filter (KF) is a recursive algorithm to estimate signal from noisy measurements. In this study it tested in predictor mode, postprocess ozone forecasts remove systematic errors. recent past and observations are used by the KF future bias. This bias correction calculated separately for, applied to, 12 different air quality (AQ) for period 11–15 August 2004, over five monitoring stations Lower Fraser Valley, British Columbia, Canada, population center complex coastal mountain...
This study investigates whether probabilistic ozone forecasts from an ensemble can be made with skill: i.e., high verification resolution and reliability. Twenty‐eight were generated over the Lower Fraser Valley, British Columbia, Canada, for 5‐day period 11–15 August 2004 compared 1‐hour averaged measurements of concentrations at five stations. The obtained by driving Community Multiscale Air Quality Model (CMAQ) model four meteorological seven emission scenarios: a control run, ±50% NO x ,...
Variations of the lifting condensation level (LCL) surface layer air are documented based on data from BLX83 field experiment in Oklahoma. For example, within a 25 km long region near Chickasha, local LCL height was found to vary by 15–30% its average height. This zone variation, centered mean height, is identified as “LCL zone”. It analogous entrainment for mixed depth. Cumulus clouds first form when top reaches bottom zone. As more overlaps and above zone, cloud cover increases. Two case...
Mixed layer depths are predicted using an entrainment equation with conservation equations. The is based on the turbulent kinetic energy for mixed layer. atmosphere idealized as having temperatures, humidities and winds constant height in boundary a step discontinuity marking top of This model tested depth observations made during 1953 Great Plains experiment, 1967 Australian Wangara 1972 Puerto Rican tropical experiment. Model calculations inversion rise offer good agreement observations....