Operational implementation of the ATOVS processing procedure in KMA and its validation

Ahn, Myoung-Hwan; Kim, Mee-Ja; Chung, Chu-Yong; Suh, Ae-Sook

doi:10.1007/bf02690798

Cited by 13 publications

(7 citation statements)

References 15 publications

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“…The performances of EnKF_30 and ERA‐I_30 were evaluated against the ATOVSL2 observations (Ahn et al, ; Bormann & Bauer, ; Li et al, ) from NOAA19, MetopA, and MetopB satellites for temperature and specific humidity. Note that some of the radiances used to derive the satellite‐retried ATOVSL2 observations have been assimilated for the ERA‐Interim and ERA5 reanalyses (that initiated ERA‐I_30 and ERA5_30) but none was used for the WRF‐EnKF (for initiating EnKF_30).…”

Section: Resultsmentioning

confidence: 99%

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Development and Evaluation of an Ensemble‐Based Data Assimilation System for Regional Reanalysis Over the Tibetan Plateau and Surrounding Regions

Zhang

Chen

et al. 2019

J Adv Model Earth Syst

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The Tibetan Plateau is regarded as the Earth's Third Pole, which is the source region of several major rivers that impact more 20% the world population. This high‐altitude region is reported to have been undergoing much greater rate of weather changes under global warming, but the existing reanalysis products are inadequate for depicting the state of the atmosphere, particularly with regard to the amount of precipitation and its diurnal cycle. An ensemble Kalman filter (EnKF) data assimilation system based on the limited‐area Weather Research and Forecasting (WRF) model was evaluated for use in developing a regional reanalysis over the Tibetan Plateau and the surrounding regions. A 3‐month prototype reanalysis over the summer months (June−August) of 2015 using WRF‐EnKF at a 30‐km grid spacing to assimilate nonradiance observations from the Global Telecommunications System was developed and evaluated against independent sounding and satellite observations in comparison to the ERA‐Interim and fifth European Centre for Medium‐Range Weather Forecasts Reanalysis (ERA5) global reanalysis. Results showed that both the posterior analysis and the subsequent 6‐ to 12‐hr WRF forecasts of the prototype regional reanalysis compared favorably with independent sounding observations, satellite‐based precipitation versus those from ERA‐Interim and ERA5 during the same period. In particular, the prototype regional reanalysis had clear advantages over the global reanalyses of ERA‐Interim and ERA5 in the analysis accuracy of atmospheric humidity, as well as in the subsequent downscale‐simulated precipitation intensity, spatial distribution, diurnal evolution, and extreme occurrence.

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Section: Resultsmentioning

confidence: 99%

“…Ahn et al, 2003;Bormann & Bauer, 2010;Li et al, 2000) from NOAA19, MetopA, and MetopB satellites for temperature…”

mentioning

confidence: 99%

Development and Evaluation of an Ensemble‐Based Data Assimilation System for Regional Reanalysis Over the Tibetan Plateau and Surrounding Regions

Zhang

Chen

et al. 2019

J Adv Model Earth Syst

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“…Toward the NARR's objective of improved hydrometeorology, the most important model upgrades include (1) the direct assimilation of satellite radiances and (2) the indirect assimilation of hourly precipitation. For the former, a distinct improvement has been observed since the 1998 upgrade of the operational vertical sounder [ Ahn et al ., ; Zhang et al ., ; Onogi et al ., ; Saha et al ., ], particularly in cloudy regions [ English et al ., ]. After this upgrade, Saha et al .…”

Section: Methodsmentioning

confidence: 99%

Tropical cyclones in the North American Regional Reanalysis: An assessment of spatial biases in location, intensity, and structure

Zick

Matyas

2015

JGR Atmospheres

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Long-term reanalysis data sets, such as the North American Regional Reanalysis (NARR) and Climate Forecast System Reanalysis (CFSR), are data-rich resources for weather and climate research. However, investigations into tropical cyclone (TC) structures are lacking. This study examines position, intensity, and structure of U.S. landfalling TCs in these data sets during 1998-2012. TC positions are determined using three dynamic and thermodynamic parameters. In NARR, positions are problematic near the domain boundary but show statistically significant improvements compared with CFSR in regions over the U.S. and near its coastlines. TC intensity is universally underestimated in both data sets, yet the pressure-wind relationship is reasonably maintained. NARR and CFSR intensities are highly correlated (r = 0.93), suggesting that these data sets are limited in a similar fashion in their generation of intensity and that advanced data assimilation techniques are unable to overcome the shortcomings of low resolutions. To investigate TC structure, a 10-storm composite is constructed using the most intense model TCs at peak intensity. Both models develop robust warm cores (T′~6-7 K), but the radius of maximum winds (>100 km) is too broad compared with storms in nature. Secondary circulation features in NARR are more realistic, particularly the shallow inflow layer, vertical motion in the inner core, and confined outflow in the upper troposphere. Results indicate that, over the U.S. and near its coastline, NARR positions and structure are competitive with or slightly improved upon CFSR. Away from the domain boundary, NARR is a suitable resource for evaluating TC positions and certain aspects of the secondary circulation.

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“…For the former, remote sensing data include vertical profile information about temperature, moisture, winds, and radiative fluxes from a constellation of satellites collectively referred to as the Television and InfraRed Observation Satellite Operational Vertical Sounder (TOVS) and—after 1998—the Advanced TOVS (ATOVS) [ Onogi et al ., ; Saha et al ., ; Berg et al ., ]. Within reanalysis systems, a distinct improvement has been observed in the upgrade from TOVS to ATOVS [ Ahn et al ., ; Zhang et al ., ; Onogi et al ., ; Saha et al ., ], particularly in cloudy regions [ English et al ., ]. Additionally, improved typhoon tracks have been attributed to direct assimilation of ATOVS microwave radiances [ Kazumori et al ., ; Zhang et al ., ].…”

Section: Data Sourcesmentioning

confidence: 99%

Tropical cyclones in the North American Regional Reanalysis: The impact of satellite‐derived precipitation over ocean

Zick

Matyas

2015

JGR Atmospheres

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Continued advancement in the realm of tropical cyclone (TC) forecasting requires a more accurate depiction of these storms at model initialization. This study examines the impact of precipitation assimilation on the representation of TCs in the North American Regional Reanalysis before and after the 2004 introduction of precipitation assimilation over ocean in the vicinity of TCs. The probability distribution function of rainfall rates indicates that light (heavy) precipitation was overforecast (underforecast) in the early time period. Since the precipitation assimilation is applied through an adjustment to the latent heating distribution, the data assimilation system in the later time period initializes a low‐level moisture and heating profile that is more conducive to the initiation of deep convection and the generation of precipitation. Consequently, the deep convection and enhanced latent heat release lead to a more robust warm‐core temperature perturbation and a better developed secondary circulation, which supplies the TC with larger quantities of moisture from the large‐scale environment. Furthermore, the evolution of TC size, which was objectively estimated though the radius of outermost closed isobar, is significantly more skillful (p < 0.05) in post‐2003 storms. Based on this study, precipitation assimilation leads to a better analysis of temperature, winds, and moisture in the vicinity of TCs, resulting in improved representations of the water budget and storm life cycle. Therefore, we conclude that efforts toward the development of precipitation assimilation techniques from radar and satellite data sets will be valuable toward the construction of improved TC forecasting tools with more authentic TC representation.

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Operational implementation of the ATOVS processing procedure in KMA and its validation

Cited by 13 publications

References 15 publications

Development and Evaluation of an Ensemble‐Based Data Assimilation System for Regional Reanalysis Over the Tibetan Plateau and Surrounding Regions

Development and Evaluation of an Ensemble‐Based Data Assimilation System for Regional Reanalysis Over the Tibetan Plateau and Surrounding Regions

Tropical cyclones in the North American Regional Reanalysis: An assessment of spatial biases in location, intensity, and structure

Tropical cyclones in the North American Regional Reanalysis: The impact of satellite‐derived precipitation over ocean

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