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Ravan Ahmadov authored and/or contributed to the following articles/publications.
To study regional-scale carbon dioxide (CO2) transport, temporal variability, and budget over the Southern California Air Basin (SoCAB) during the California Research at the Nexus of Air Quality and Climate Change (CalNex) 2010 campaign period, a model that couples the Weather Research and Forecasting (WRF) Model with the Vegetation Photosynthes...
Institution National Oceanic and Atmospheric Administration - NOAA
Institution National Oceanic and Atmospheric Administration - NOAA
Recent wildfires in the U.S. and abroad have underscored the far-reaching effects that smoke from wildfires has on lives and industries, impacting air quality, aviation, solar energy generation, and more. As a result, demand has increased for reliable and accurate forecasts of smoke emanating from wildfires. To a...
The global Flow-following finite-volume Icosahedral Model (FIM), which was developed in the Global Systems Laboratory of NOAA/ESRL, has been coupled inline with aerosol and gas-phase chemistry schemes of different complexity using the chemistry and aerosol packages from WRF-Chem v3.7, named as FIM-Chem v1. The three chemistry schemes include 1) ...
Institutions National Oceanic and Atmospheric Administration - NOAA Earth System Research Laboratory - ESRL
How does a Pinatubo‐size Volcanic Cloud Reach the Middle Stratosphere?
Volcanic explosions are the most critical replenishing mechanism of the stratospheric aerosol Junge layer. A fresh volcanic cloud comprises mostly sulfur‐bearing gases, volcanic ash, and water vapor. It is commonly assumed that only sulfate aerosols remain in an aged volcanic cloud. Accurate simulation of the initial evolution of multicomponent ...
Institution National Oceanic and Atmospheric Administration - NOAA
Wildfire smoke is one of the most significant concerns of human and environmental health, associated with its substantial impacts on air quality, weather, and climate. However, biomass burning emissions and smoke remain among the largest sources of uncertainties in air quality forecasts. In this study, we evaluate the smoke emissions and plume f...
Institution National Oceanic and Atmospheric Administration - NOAA
Solar radiation is the ultimate source of energy flowing through the atmosphere; it fuels all atmospheric motions. The visible-wavelength range of solar radiation represents a significant contribution to the earth's energy budget, and visible light is a vital indicator for the composition and thermodynamic processes of the atmosphere from the sm...
Institution National Oceanic and Atmospheric Administration - NOAA
Nitrous acid (HONO) and nitryl chloride (ClNO2) – through their photolysis – can have profound effects on the nitrogen cycle and oxidation capacity of the lower troposphere. Previous numerical studies have separately considered and investigated the sources/processes of these compounds and their roles in the fate of reactive nitrogen and the prod...
Institution National Oceanic and Atmospheric Administration - NOAA
Improving dust simulations in WRF-Chem v4.1.3 coupled with the GOCART aerosol module
In this paper, we rectify inconsistencies that emerge in the Weather Research and Forecasting model with chemistry (WRF-Chem) v3.2 code when using the Goddard Chemistry Aerosol Radiation and Transport (GOCART) aerosol module. These inconsistencies have been reported, and corrections have been implemented in WRF-Chem v4.1.3. Here, we use a WRF-Ch...
Institution National Oceanic and Atmospheric Administration - NOAA
Wildfire smoke aerosols, once emitted, can transport over long distances and affect surface air quality in downwind regions. In New York State (NYS), fine particulate matter (PM2.5) concentration continues to decrease due to anthropogenic emission reductions and regulatory initiatives in recent years. Smoke aerosols, however, are projected to in...
Institution National Oceanic and Atmospheric Administration - NOAA
The evolution of organic aerosols (OAs) and their precursors in the boundary layer (BL) of the Colorado Front Range during the Front Range Air Pollution and Photochemistry Éxperiment (FRAPPÉ, July–August 2014) was analyzed by in situ measurements and chemical transport modeling. Measurements indicated significant production of secondary OA (SOA)...
Institutions Earth System Research Laboratory - ESRL National Oceanic and Atmospheric Administration - NOAA
Development of a Fuel-Based Oil and Gas Inventory of Nitrogen Oxides Emissions
In this study, we develop an alternative Fuel-based Oil and Gas inventory (FOG) of nitrogen oxides (NOx) from oil and gas production using publicly available fuel use records and emission factors reported in the literature. FOG is compared with the Environmental Protection Agency’s 2014 National Emissions Inventory (NEI) and with new top-down es...
Modeling Ozone in the Eastern U.S. using a Fuel-Based Mobile Source Emissions Inventory
Recent studies suggest overestimates in current U.S. emission inventories of nitrogen oxides (NOx = NO + NO2). Here, we expand a previously developed fuel-based inventory of motor-vehicle emissions (FIVE) to the continental U.S. for the year 2013, and evaluate our estimates of mobile source emissions with the U.S. Environmental Protection Agency...
Institution National Oceanic and Atmospheric Administration - NOAA
Nitrous acid formation in a snow-free wintertime polluted rural area
Nitrous acid (HONO) photolysis is an important source of hydroxyl radicals (OH) in the lower atmosphere, in particular in winter when other OH sources are less efficient. The nighttime formation of HONO and its photolysis in the early morning have long been recognized as an important contributor to the OH budget in polluted environments. Over th...
The Weather Research and Forecasting Model: Overview, System Efforts, and Future Directions
Since its initial release in 2000, the Weather Research and Forecasting (WRF) Model has become one of the world’s most widely-used numerical weather prediction models. Designed to serve both research and operational needs, it has grown to offer a spectrum of options and capabilities for a wide range of applications. In addition, it underlies a n...
Institutions National Center for Atmospheric Research - NCAR National Oceanic and Atmospheric Administration - NOAA
Diagnostic fields developed for hourly updated NOAA weather models
This document describes methods for diagnosing non-prognostic variables from explicit prognostic variables from hourly updated NOAA models. Many of these diagnostics have been developed for specific forecast applications for downstream forecast users over the years; these variables have been output from the Rapid Update Cycle (RUC) model prior t...
Institution National Oceanic and Atmospheric Administration - NOAA
Megafires and thick smoke portend big problems for migratory birds
In 2020, the fire season affecting the western United States reached unprecedented levels. The 116 fires active in September consumed nearly 20,822 km2 (https://inciweb.nwcg.gov/accessible-view/ Accessed 2020-09-29) with 80% of this footprint (16,567 km2) from 68 fires occurring within California, Oregon, and Washington. Although the 2020 fire s...
Quantifying Carbon Monoxide Emissions on the Scale of Large Wildfires
The University of Colorado Airborne Solar Occultation Flux (CU AirSOF) instrument conducted the first suborbital carbon monoxide (CO) mass flux measurements on the scale of large wildfires, showing that the destructive fires in northern California in October 2017 emitted 2040 ± 316 tonnes CO hr−1. Pyrogenic estimates from 7 satellite-based emiss...
High-resolution smoke forecasting for the 2018 Camp Fire in California
Smoke from the 2018 Camp Fire in Northern California blanketed a large part of the region for two weeks, creating poor air quality in the “unhealthy” range for millions of people. The NOAA Global System Laboratory’s HRRR-Smoke model was operating experimentally in real time during the Camp Fire. Here, output from the HRRR-Smoke model is compared...
Institution National Oceanic and Atmospheric Administration - NOAA
The uptake of dinitrogen pentoxide (N2O5) on aerosol surfaces and the subsequent production of nitryl chloride (ClNO2) can have a significant impact on the oxidising capability and thus on secondary pollutants such as ozone. The range of such an impact, however, has not been well quantified in different geographical regions. In this study, we ap...
Recent increases in oil and natural gas (NG) production throughout the western US have come with scientific and public interest in emission rates, air quality and climate impacts related to this industry. This study uses a regional-scale air quality model (WRF-Chem) to simulate high ozone (O3) episodes during the winter of 2013 over the Uinta Ba...
Institution Earth System Research Laboratory - ESRL
WRF-Chem Version 3.8.1 Users Guide
The WRF-Chem User's Guide is designed to provide the reader with information specific to the chemistry part of the WRF model and its potential applications. It will provide the user a description of the WRF-Chem model and discuss specific issues related to generating a forecast that includes chemical constituents beyond what is typically used by...
Institutions National Center for Atmospheric Research - NCAR National Oceanic and Atmospheric Administration - NOAA
The High-Resolution Rapid Refresh (HRRR) is a convection-allowing implementation of the Weather Research and Forecasting model (WRF-ARW) with hourly data assimilation that covers the conterminous United States and Alaska and runs in real time at the NOAA National Centers for Environmental Prediction. Implemented operationally at NOAA/NCEP in 201...
Institution National Oceanic and Atmospheric Administration - NOAA
Prototype of a Warn-on-Forecast System for Smoke (WoFS-Smoke)
This research begins the process of creating an ensemble-based forecast system for smoke aerosols generated from wildfires using a modified version of the National Severe Storms Laboratory (NSSL) Warn-on-Forecast System (WoFS). The existing WoFS has proven effective in generating short-term (0–3 h) probabilistic forecasts of high-impact weather ...
Institution National Oceanic and Atmospheric Administration - NOAA
Abstract Image Carbonaceous emissions from wildfires are a dynamic mixture of gases and particles that have important impacts on air quality and climate. Emissions that feed atmospheric models are estimated using burned area and fire radiative power (FRP) methods that rely on satellite products. These approaches show wide variability and have l...
The National Oceanic and Atmospheric Administration (NOAA)'s National Weather Service (NWS) is on its way to deploying various operational prediction applications using the Unified Forecast System (https://ufscommunity.org/, last access: 18 June 2022), a community-based coupled, comprehensive Earth modeling system. An aerosol model component dev...
Institutions Earth System Research Laboratory - ESRL National Oceanic and Atmospheric Administration - NOAA
Plume height plays a vital role in wildfire smoke dispersion and the subsequent effects on air quality and human health. In this study, we assess the impact of different plume rise schemes on predicting the dispersion of wildfire air pollution, and the exceedances of the National Ambient Air Quality Standards (NAAQS) for fine particulate matter ...
Institution National Oceanic and Atmospheric Administration - NOAA
We use the Weather Research and Forecasting with Chemistry (WRF-Chem) model with new implementations of GOES-16 wildfire emissions and plume rise based on fire radiative power (FRP) to interpret aerosol observations during the 2019 NASA-NOAA FIREX-AQ field campaign and perform model evaluations. We compare simulated aerosol concentrations and op...
Institutions Earth System Research Laboratory - ESRL National Oceanic and Atmospheric Administration - NOAA
Were Wildfires Responsible for the Unusually High Surface Ozone in 2 Colorado during 2021?
Ground-level ozone (O3) was unusually high in northern Colorado in the summer of 2021 with maximum daily 8-hr average (MDA8) concentrations 6 to 8 parts-per-billion by volume (ppbv) higher than in 2019, 2020, or 2022. One or more of the monitors on the Colorado Front Range exceeded the 2015 U.S. National Ambient Air Quality Standard (NAAQS) of 7...
Institution National Oceanic and Atmospheric Administration - NOAA
Assimilation of Aerosol Optical Depth Into the Warn-on-Forecast System for Smoke (WoFS-Smoke)
This research extends the Warn-on-Forecast System for Smoke (WoFS-Smoke) by adding the capability to assimilate aerosol optical depth (AOD) retrievals from the Geostationary Operational Environmental Satellite Series-R (GOES-R) satellites. The WoFS is a rapidly cycling, ensemble-based analysis and forecasting system designed to generate short te...
Institution National Oceanic and Atmospheric Administration - NOAA
Where and when wildfires occur, what pollutants they emit, how the chemistry of smoke changes in the atmosphere, and what impact this air pollution has on human health and well-being are questions explored across different scientific disciplines. Landscape Fire, Smoke, and Health: Linking Biomass Burning Emissions to Human Well-Being is desig...
Population co-exposure to extreme heat and wildfire smoke pollution in California during 2020
Excessive warming from climate change has increased the total wildfire burned area over the past several decades in California. This has increased population exposure to both hazardous concentrations of air pollutants from fires such as fine particulate matter (smoke PM2.5) and extreme heat events. Exposure to PM2.5 and extreme heat are individu...
Institution National Oceanic and Atmospheric Administration - NOAA
Injections of wildfire smoke plumes into the free troposphere impact air quality, yet model forecasts of injections are poor. Here, we use aircraft observations obtained during the 2019 western US wildfires (FIREX-AQ) to evaluate a commonly used smoke plume rise parameterization in two atmospheric chemistry-transport models (WRF-Chem and HRRR-Sm...
Institution National Oceanic and Atmospheric Administration - NOAA
Wildfire activity in the western U.S. has increased in frequency and severity in recent decades. Wildfire smoke emissions contribute to elevated fine particulate matter (PM2.5) concentrations that are dangerous to public health. Due to the outdoor and physically demanding nature of their work, agricultural workers are particularly vulnerable to ...
Institution National Oceanic and Atmospheric Administration - NOAA
A physics suite under development at NOAA's Global Systems Laboratory (GSL) includes the aerosol-aware double-moment Thompson–Eidhammer microphysics (TH-E MP) scheme. This microphysics scheme uses two aerosol variables (concentrations of water-friendly aerosol (WFA) and ice-friendly aerosol (IFA) numbers) to include interactions with some of the...
Institution National Oceanic and Atmospheric Administration - NOAA
Ingesting GOES-16 fire radiative power retrievals into Warn-on-Forecast System for Smoke
Background The record number of wildfires in the United States in recent years has led to an increased focus on developing tools to accurately forecast their impacts at high spatial and temporal resolutions. Aims The Warn-on-Forecast System for Smoke (WoFS-Smoke) was developed to improve these forecasts using wildfire properties retrieved f...
Institution National Oceanic and Atmospheric Administration - NOAA
Results are presented from the Rum Creek fire during the California Fire Dynamics Experiment (CalFiDE). An instrumented payload aboard the NOAA Twin Otter (TO) aircraft, which included a scanning micro-pulsed Doppler lidar (DL) and in situ chemistry packages, was used to address the evolution of a buoyant plume jet (BPJ) and transport dynamics o...
Institution National Oceanic and Atmospheric Administration - NOAA
A better representation of VOC chemistry in WRF-Chem and its impact on ozone over Los Angeles
The declining trend in vehicle emissions has underscored the growing significance of Volatile Organic Compound (VOC) emissions from Volatile Chemical Products (VCP). However, accurately representing VOC chemistry in simplified chemical mechanisms remains challenging due to its chemical complexity including speciation and reactivity. Previous stu...
Institution National Oceanic and Atmospheric Administration - NOAA