Typhoon Warm-Core Structures Derived from FY-3D MWTS-2 Observations
In this study, the three-dimensional (3D) warm-core structures of the Northwest Pacific typhoons Francisco, Lekima, and Krosa in August 2019 are retrieved from the Fengyun-3D (FY-3D) microwave temperature sounder-2 (MWTS-2) observations of brightness temperature. Due to the lack of two window channe...
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| Format: | Article |
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MDPI AG
2021-09-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/13/18/3730 |
| _version_ | 1827681396319059968 |
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| author | Zeyi Niu Xiaolei Zou Wei Huang |
| author_facet | Zeyi Niu Xiaolei Zou Wei Huang |
| author_sort | Zeyi Niu |
| collection | DOAJ |
| description | In this study, the three-dimensional (3D) warm-core structures of the Northwest Pacific typhoons Francisco, Lekima, and Krosa in August 2019 are retrieved from the Fengyun-3D (FY-3D) microwave temperature sounder-2 (MWTS-2) observations of brightness temperature. Due to the lack of two window channels at 23.8 GHz and 31.4 GHz, an empirical cloud detection algorithm based on 50.3 GHz bias-corrected observations-minus-backgrounds is applied to obtain clear-sky observations for the multiple linear regression retrieval algorithm. The MWTS-2 cloud-affected channels 3–5 are not used to retrieve temperatures under cloudy conditions to eliminate low-tropospheric cold anomalies. The multiple linear regression coefficients are obtained based on MWTS-2 brightness temperatures and the temperatures from the European Centre for Medium-Range Weather Forecasts Reanalysis-5 (ERA5) in the training period of three weeks before the month of targeted typhoons. The proposed MWTS-2 warm-core retrieval can well capture the radial and vertical temporal evolutions of the temperature anomalies of the typhoons Francisco, Lekima, and Krosa. The sizes of the warm-core anomalies of typhoons Lekima and Krosa retrieved by the MWTS-2 are horizontally and vertically similar to and stronger than those of the ERA5. Compared with the ERA5 reanalysis in August 2019, the biases for MWTS-2 temperature retrievals are smaller than ±0.25 K, with root-mean-square errors (RMSEs) smaller than and 2.0 K at all altitudes. Additionally, the location of the 250-hPa maximum temperature anomaly retrieved by the MWTS-2 is closer to the best track than that of the ERA5. A weak warm-core around 200 hPa and a cold-core anomaly in the middle troposphere are also found in the outer rain bands region due to the effect of evaporation of rainfall. |
| first_indexed | 2024-03-10T07:14:33Z |
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| id | doaj.art-838cd288e2754759a78bf75455fae1dd |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-10T07:14:33Z |
| publishDate | 2021-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-838cd288e2754759a78bf75455fae1dd2023-11-22T15:07:28ZengMDPI AGRemote Sensing2072-42922021-09-011318373010.3390/rs13183730Typhoon Warm-Core Structures Derived from FY-3D MWTS-2 ObservationsZeyi Niu0Xiaolei Zou1Wei Huang2Key Laboratory of Numerical Modeling for Tropical Cyclone of the China Meteorological Administration, Shanghai Typhoon Institute, Shanghai 200030, ChinaJoint Center of Data Assimilation for Research and Application, Nanjing University of Information and Science & Technology, Nanjing 210044, ChinaKey Laboratory of Numerical Modeling for Tropical Cyclone of the China Meteorological Administration, Shanghai Typhoon Institute, Shanghai 200030, ChinaIn this study, the three-dimensional (3D) warm-core structures of the Northwest Pacific typhoons Francisco, Lekima, and Krosa in August 2019 are retrieved from the Fengyun-3D (FY-3D) microwave temperature sounder-2 (MWTS-2) observations of brightness temperature. Due to the lack of two window channels at 23.8 GHz and 31.4 GHz, an empirical cloud detection algorithm based on 50.3 GHz bias-corrected observations-minus-backgrounds is applied to obtain clear-sky observations for the multiple linear regression retrieval algorithm. The MWTS-2 cloud-affected channels 3–5 are not used to retrieve temperatures under cloudy conditions to eliminate low-tropospheric cold anomalies. The multiple linear regression coefficients are obtained based on MWTS-2 brightness temperatures and the temperatures from the European Centre for Medium-Range Weather Forecasts Reanalysis-5 (ERA5) in the training period of three weeks before the month of targeted typhoons. The proposed MWTS-2 warm-core retrieval can well capture the radial and vertical temporal evolutions of the temperature anomalies of the typhoons Francisco, Lekima, and Krosa. The sizes of the warm-core anomalies of typhoons Lekima and Krosa retrieved by the MWTS-2 are horizontally and vertically similar to and stronger than those of the ERA5. Compared with the ERA5 reanalysis in August 2019, the biases for MWTS-2 temperature retrievals are smaller than ±0.25 K, with root-mean-square errors (RMSEs) smaller than and 2.0 K at all altitudes. Additionally, the location of the 250-hPa maximum temperature anomaly retrieved by the MWTS-2 is closer to the best track than that of the ERA5. A weak warm-core around 200 hPa and a cold-core anomaly in the middle troposphere are also found in the outer rain bands region due to the effect of evaporation of rainfall.https://www.mdpi.com/2072-4292/13/18/3730MWTS-2ERA5typhoon warm-core retrieval |
| spellingShingle | Zeyi Niu Xiaolei Zou Wei Huang Typhoon Warm-Core Structures Derived from FY-3D MWTS-2 Observations Remote Sensing MWTS-2 ERA5 typhoon warm-core retrieval |
| title | Typhoon Warm-Core Structures Derived from FY-3D MWTS-2 Observations |
| title_full | Typhoon Warm-Core Structures Derived from FY-3D MWTS-2 Observations |
| title_fullStr | Typhoon Warm-Core Structures Derived from FY-3D MWTS-2 Observations |
| title_full_unstemmed | Typhoon Warm-Core Structures Derived from FY-3D MWTS-2 Observations |
| title_short | Typhoon Warm-Core Structures Derived from FY-3D MWTS-2 Observations |
| title_sort | typhoon warm core structures derived from fy 3d mwts 2 observations |
| topic | MWTS-2 ERA5 typhoon warm-core retrieval |
| url | https://www.mdpi.com/2072-4292/13/18/3730 |
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