Tanya Smirnova - Academia.edu (original) (raw)

Papers by Tanya Smirnova

The growing influence of biomass burning emissions on air quality, human health, and feedbacks to... more The growing influence of biomass burning emissions on air quality, human health, and feedbacks to the climate system has become undeniable in recent years. Recognized impacts include enhanced emissions of greenhouse gases changes in atmospheric chemistry, deposition of trace gases and particles onto Arctic surfaces, and altered patterns of precipitation. Chemical Transport Models use a variety of methods to include

EGU General Assembly Conference Abstracts, Apr 1, 2018

EGU General Assembly Conference Abstracts, Apr 1, 2017

EGU General Assembly Conference Abstracts, Apr 1, 2016

The 3-km convective-allowing High-Resolution Rapid Refresh (HRRR) is a US NOAA hourly updating we... more The 3-km convective-allowing High-Resolution Rapid Refresh (HRRR) is a US NOAA hourly updating weather forecast model that use a specially configured version of the Advanced Research WRF (ARW) model and assimilate many novel and most conventional observation types on an hourly basis using Gridpoint Statistical Interpolation (GSI). Included in this assimilation is a procedure for initializing ongoing precipitation systems from observed radar reflectivity data (and proxy reflectivity from lightning and satellite data), a cloud analysis to initialize stable layer clouds from METAR and satellite observations, and special techniques to enhance retention of surface observation information. The HRRR is run hourly out to 15 forecast hours over a domain covering the entire conterminous United States using initial and boundary conditions from the hourly-cycled 13km Rapid Refresh (RAP, using similar physics and data assimilation) covering North America and a significant part of the Northern Hemisphere. The HRRR is continually developed and refined at NOAA's Earth System Research Laboratory, and an initial version was implemented into the operational NOAA/NCEP production suite in September 2014. Ongoing experimental RAP and HRRR model development throughout 2014 and 2015 has culminated in a set of data assimilation and model enhancements that will be incorporated into the first simultaneous upgrade of both the operational RAP and HRRR that is scheduled for spring 2016 at NCEP. This presentation will discuss the operational RAP and HRRR changes contained in this upgrade. The RAP domain is being expanded to encompass the NAM domain and the forecast lengths of both the RAP and HRRR are being extended. RAP and HRRR assimilation enhancements have focused on (1) extending surface data assimilation to include mesonet observations and improved use of all surface observations through better background estimates of 2-m temperature and dewpoint including projection of 2-m temperature observations through the model boundary layer and (2) extending the use of radar observations to include both radial velocity and 3-D retrieval of rain hydrometeors from observed radar reflectivities in the warm-season. The RAP hybrid EnKF 3D-variational data assimilation will increase weighting of GFS ensemble-based background error covariance estimation and introduce this hybrid data assimilation configuration in the HRRR. Enhancement of RAP and HRRR model physics include improved land surface and boundary layer prediction using the updated Mellor-Yamada-Nakanishi-Niino (MYNN) parameterization scheme, Grell-Freitas-Olson (GFO) shallow and deep convective parameterization, aerosol-aware Thompson microphysics and upgraded Rapid Update Cycle (RUC) land-surface model. The presentation will highlight improvements in the RAP and HRRR model physics to reduce certain systematic forecast biases including a warm and dry daytime bias over the central and eastern CONUS during the warm season along with improved convective forecasts in more weakly-forced diurnally-driven events. Examples of RAP and HRRR forecast improvements will be demonstrated through both retrospective and real-time verification statistics and case-study examples.

Weather and Forecasting, May 15, 2020

A new hybrid, sigma-pressure vertical coordinate was recently added to the Weather Research and F... more A new hybrid, sigma-pressure vertical coordinate was recently added to the Weather Research and Forecasting (WRF) Model in an effort to reduce numerical noise in the model equations near complex terrain. Testing of this hybrid, terrain-following coordinate was undertaken in the WRF-based Rapid Refresh (RAP) and High-Resolution Rapid Refresh (HRRR) models to assess impacts on retrospective and real-time simulations. Initial cold-start simulations indicated that the majority of differences between the hybrid and traditional sigma coordinate were confined to regions downstream of mountainous terrain and focused in the upper levels. Week-long retrospective simulations generally resulted in small improvements for the RAP, and a neutral impact in the HRRR when the hybrid coordinate was used. However, one possibility is that the inclusion of data assimilation in the experiments may have minimized differences between the vertical coordinates. Finally, analysis of turbulence forecasts with the new hybrid coordinate indicate a significant reduction in spurious vertical motion over the full length of the Rocky Mountains. Overall, the results indicate a potential to improve forecast metrics through implementation of the hybrid coordinate, particularly at upper levels, and downstream of complex terrain.

The 30-year simulations of seasonal snow cover in 22 physically based models driven with bias-cor... more The 30-year simulations of seasonal snow cover in 22 physically based models driven with bias-corrected meteorological reanalyses are examined at four sites with long records of snow observations. Annual snow cover durations differ widely between models, but interannual variations are strongly correlated because of the common driving data. No significant trends are observed in starting dates for seasonal snow cover, but there are significant trends towards snow cover ending earlier at two of the sites in observations and most of the models. A simplified model with just two parameters controlling solar radiation and sensible heat contributions to snowmelt spans the ranges of snow cover durations and trends. This model predicts that sites where snow persists beyond annual peaks in solar radiation and air temperature will experience rapid decreases in snow cover duration with warming as snow begins to melt earlier and at times of year with more energy available for melting.

EGU General Assembly Conference Abstracts, Apr 1, 2018

EGU General Assembly Conference Abstracts, Apr 1, 2017

Monthly Weather Review, 2015

A hydrostatic global weather prediction model based on an icosahedral horizontal grid and a hybri... more A hydrostatic global weather prediction model based on an icosahedral horizontal grid and a hybrid terrain-following/isentropic vertical coordinate is described. The model is an extension to three spatial dimensions of a previously developed, icosahedral, shallow-water model featuring user-selectable horizontal resolution and employing indirect addressing techniques. The vertical grid is adaptive to maximize the portion of the atmosphere mapped into the isentropic coordinate subdomain. The model, best described as a stacked shallow-water model, is being tested extensively on real-time medium-range forecasts to ready it for possible inclusion in operational multimodel ensembles for medium-range to seasonal prediction.

Accurate estimation of snow water equivalent over the United States and adjacent areas is obvious... more Accurate estimation of snow water equivalent over the United States and adjacent areas is obviously critical for subsequent seasonal and short-range atmospheric and hydrological model forecasts. It is also essential for water planning for a variety of important activities in ...

The next generation of the 1h Rapid Update Cycle (RUC) is being readied for operational use at th... more The next generation of the 1h Rapid Update Cycle (RUC) is being readied for operational use at the 13 km scale. The Rapid Refresh (RR)

Initialization refers to the process in which meteorological analyses are modified and applied to... more Initialization refers to the process in which meteorological analyses are modified and applied to a numerical model grid. Imbalance between

A significant RUC upgrade bundle is planned at NCEP for spring 2008, of which the most important ... more A significant RUC upgrade bundle is planned at NCEP for spring 2008, of which the most important change is the hourly assimilation of 3-d radar

introduced the first US operational model to be run at intervals less than the standard 12h betwe... more introduced the first US operational model to be run at intervals less than the standard 12h between rawinsonde observations. Dubbed the Rapid Update Cycle, or RUC, this model was initially run as the forecast component of an intermittent (3-h interval) assimilation cycle over a domain slightly larger than the coterminous US. This more rapid updating was made possible by increasing number of “offtime ” observations, particularly from commercial aircraft and from the experimental NOAA Profiler Network that had come into existence a few years earlier. Over the years, both the analysis and model have undergone substantial upgrades and this model is now run in a configuration with 13km horizontal grid spacing and 50 hybrid-sigma-isentropic levels over a domain covering the coterminous US, southern Canada, northern Mexico and adjacent waters at an assimilation frequency of one hour. A full description of the RUC as it existed in 2003 can be found in Benjamin et al (2004a,b). A discussion ...

The growing influence of biomass burning emissions on air quality, human health, and feedbacks to... more The growing influence of biomass burning emissions on air quality, human health, and feedbacks to the climate system has become undeniable in recent years. Recognized impacts include enhanced emissions of greenhouse gases changes in atmospheric chemistry, deposition of trace gases and particles onto Arctic surfaces, and altered patterns of precipitation. Chemical Transport Models use a variety of methods to include

EGU General Assembly Conference Abstracts, Apr 1, 2018

EGU General Assembly Conference Abstracts, Apr 1, 2017

EGU General Assembly Conference Abstracts, Apr 1, 2016

The 3-km convective-allowing High-Resolution Rapid Refresh (HRRR) is a US NOAA hourly updating we... more The 3-km convective-allowing High-Resolution Rapid Refresh (HRRR) is a US NOAA hourly updating weather forecast model that use a specially configured version of the Advanced Research WRF (ARW) model and assimilate many novel and most conventional observation types on an hourly basis using Gridpoint Statistical Interpolation (GSI). Included in this assimilation is a procedure for initializing ongoing precipitation systems from observed radar reflectivity data (and proxy reflectivity from lightning and satellite data), a cloud analysis to initialize stable layer clouds from METAR and satellite observations, and special techniques to enhance retention of surface observation information. The HRRR is run hourly out to 15 forecast hours over a domain covering the entire conterminous United States using initial and boundary conditions from the hourly-cycled 13km Rapid Refresh (RAP, using similar physics and data assimilation) covering North America and a significant part of the Northern Hemisphere. The HRRR is continually developed and refined at NOAA's Earth System Research Laboratory, and an initial version was implemented into the operational NOAA/NCEP production suite in September 2014. Ongoing experimental RAP and HRRR model development throughout 2014 and 2015 has culminated in a set of data assimilation and model enhancements that will be incorporated into the first simultaneous upgrade of both the operational RAP and HRRR that is scheduled for spring 2016 at NCEP. This presentation will discuss the operational RAP and HRRR changes contained in this upgrade. The RAP domain is being expanded to encompass the NAM domain and the forecast lengths of both the RAP and HRRR are being extended. RAP and HRRR assimilation enhancements have focused on (1) extending surface data assimilation to include mesonet observations and improved use of all surface observations through better background estimates of 2-m temperature and dewpoint including projection of 2-m temperature observations through the model boundary layer and (2) extending the use of radar observations to include both radial velocity and 3-D retrieval of rain hydrometeors from observed radar reflectivities in the warm-season. The RAP hybrid EnKF 3D-variational data assimilation will increase weighting of GFS ensemble-based background error covariance estimation and introduce this hybrid data assimilation configuration in the HRRR. Enhancement of RAP and HRRR model physics include improved land surface and boundary layer prediction using the updated Mellor-Yamada-Nakanishi-Niino (MYNN) parameterization scheme, Grell-Freitas-Olson (GFO) shallow and deep convective parameterization, aerosol-aware Thompson microphysics and upgraded Rapid Update Cycle (RUC) land-surface model. The presentation will highlight improvements in the RAP and HRRR model physics to reduce certain systematic forecast biases including a warm and dry daytime bias over the central and eastern CONUS during the warm season along with improved convective forecasts in more weakly-forced diurnally-driven events. Examples of RAP and HRRR forecast improvements will be demonstrated through both retrospective and real-time verification statistics and case-study examples.

Weather and Forecasting, May 15, 2020

A new hybrid, sigma-pressure vertical coordinate was recently added to the Weather Research and F... more A new hybrid, sigma-pressure vertical coordinate was recently added to the Weather Research and Forecasting (WRF) Model in an effort to reduce numerical noise in the model equations near complex terrain. Testing of this hybrid, terrain-following coordinate was undertaken in the WRF-based Rapid Refresh (RAP) and High-Resolution Rapid Refresh (HRRR) models to assess impacts on retrospective and real-time simulations. Initial cold-start simulations indicated that the majority of differences between the hybrid and traditional sigma coordinate were confined to regions downstream of mountainous terrain and focused in the upper levels. Week-long retrospective simulations generally resulted in small improvements for the RAP, and a neutral impact in the HRRR when the hybrid coordinate was used. However, one possibility is that the inclusion of data assimilation in the experiments may have minimized differences between the vertical coordinates. Finally, analysis of turbulence forecasts with the new hybrid coordinate indicate a significant reduction in spurious vertical motion over the full length of the Rocky Mountains. Overall, the results indicate a potential to improve forecast metrics through implementation of the hybrid coordinate, particularly at upper levels, and downstream of complex terrain.

The 30-year simulations of seasonal snow cover in 22 physically based models driven with bias-cor... more The 30-year simulations of seasonal snow cover in 22 physically based models driven with bias-corrected meteorological reanalyses are examined at four sites with long records of snow observations. Annual snow cover durations differ widely between models, but interannual variations are strongly correlated because of the common driving data. No significant trends are observed in starting dates for seasonal snow cover, but there are significant trends towards snow cover ending earlier at two of the sites in observations and most of the models. A simplified model with just two parameters controlling solar radiation and sensible heat contributions to snowmelt spans the ranges of snow cover durations and trends. This model predicts that sites where snow persists beyond annual peaks in solar radiation and air temperature will experience rapid decreases in snow cover duration with warming as snow begins to melt earlier and at times of year with more energy available for melting.

EGU General Assembly Conference Abstracts, Apr 1, 2018

EGU General Assembly Conference Abstracts, Apr 1, 2017

Monthly Weather Review, 2015

A hydrostatic global weather prediction model based on an icosahedral horizontal grid and a hybri... more A hydrostatic global weather prediction model based on an icosahedral horizontal grid and a hybrid terrain-following/isentropic vertical coordinate is described. The model is an extension to three spatial dimensions of a previously developed, icosahedral, shallow-water model featuring user-selectable horizontal resolution and employing indirect addressing techniques. The vertical grid is adaptive to maximize the portion of the atmosphere mapped into the isentropic coordinate subdomain. The model, best described as a stacked shallow-water model, is being tested extensively on real-time medium-range forecasts to ready it for possible inclusion in operational multimodel ensembles for medium-range to seasonal prediction.

Accurate estimation of snow water equivalent over the United States and adjacent areas is obvious... more Accurate estimation of snow water equivalent over the United States and adjacent areas is obviously critical for subsequent seasonal and short-range atmospheric and hydrological model forecasts. It is also essential for water planning for a variety of important activities in ...

The next generation of the 1h Rapid Update Cycle (RUC) is being readied for operational use at th... more The next generation of the 1h Rapid Update Cycle (RUC) is being readied for operational use at the 13 km scale. The Rapid Refresh (RR)

Initialization refers to the process in which meteorological analyses are modified and applied to... more Initialization refers to the process in which meteorological analyses are modified and applied to a numerical model grid. Imbalance between

A significant RUC upgrade bundle is planned at NCEP for spring 2008, of which the most important ... more A significant RUC upgrade bundle is planned at NCEP for spring 2008, of which the most important change is the hourly assimilation of 3-d radar

introduced the first US operational model to be run at intervals less than the standard 12h betwe... more introduced the first US operational model to be run at intervals less than the standard 12h between rawinsonde observations. Dubbed the Rapid Update Cycle, or RUC, this model was initially run as the forecast component of an intermittent (3-h interval) assimilation cycle over a domain slightly larger than the coterminous US. This more rapid updating was made possible by increasing number of “offtime ” observations, particularly from commercial aircraft and from the experimental NOAA Profiler Network that had come into existence a few years earlier. Over the years, both the analysis and model have undergone substantial upgrades and this model is now run in a configuration with 13km horizontal grid spacing and 50 hybrid-sigma-isentropic levels over a domain covering the coterminous US, southern Canada, northern Mexico and adjacent waters at an assimilation frequency of one hour. A full description of the RUC as it existed in 2003 can be found in Benjamin et al (2004a,b). A discussion ...