A simplified, axisymmetric, one-layer model of tropical cyclone intensification is presented. The model is based on Salmon’s wave-vortex approximation, which can describe flows with high Rossby number and low Froude number. After introducing an additional approximation designed to filter propagating inertiagravity waves, the problem is reduced to the prediction of potential vorticity (PV) and the inversion of this PV to obtain the balanced wind and mass fields. This PV prediction/inversion problem is solved analytically for two types of forcing: a two-region model in which there is nonzero forcing in the cyclone core and zero forcing in the far-field, and a three-region model in which there is non-zero forcing in both the cyclone core and the eyewall, with zero forcing in the far-field. The solutions of the two-region model provide insight into why tropical cyclones can have long incubation times before rapid intensification and how the size of the mature vortex can be influenced by the size of the initial vortex. The solutions of the three-region model provide insight into the formation of hollow PV structures and the inward movement of angular momentum surfaces across the radius of maximum wind.
{"title":"Forced, Balanced Model of Tropical Cyclone Intensification","authors":"W. Schubert, C. Slocum, Richard K. Taft","doi":"10.2151/JMSJ.2016-007","DOIUrl":"https://doi.org/10.2151/JMSJ.2016-007","url":null,"abstract":"A simplified, axisymmetric, one-layer model of tropical cyclone intensification is presented. The model is based on Salmon’s wave-vortex approximation, which can describe flows with high Rossby number and low Froude number. After introducing an additional approximation designed to filter propagating inertiagravity waves, the problem is reduced to the prediction of potential vorticity (PV) and the inversion of this PV to obtain the balanced wind and mass fields. This PV prediction/inversion problem is solved analytically for two types of forcing: a two-region model in which there is nonzero forcing in the cyclone core and zero forcing in the far-field, and a three-region model in which there is non-zero forcing in both the cyclone core and the eyewall, with zero forcing in the far-field. The solutions of the two-region model provide insight into why tropical cyclones can have long incubation times before rapid intensification and how the size of the mature vortex can be influenced by the size of the initial vortex. The solutions of the three-region model provide insight into the formation of hollow PV structures and the inward movement of angular momentum surfaces across the radius of maximum wind.","PeriodicalId":17476,"journal":{"name":"Journal of the Meteorological Society of Japan","volume":"94 1","pages":"119-135"},"PeriodicalIF":3.1,"publicationDate":"2018-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2151/JMSJ.2016-007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42642949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mayumi Yoshida, M. Kikuchi, T. Nagao, H. Murakami, Tomoyuki Nomaki, A. Higurashi
{"title":"Common Retrieval of Aerosol Properties for Imaging Satellite Sensors","authors":"Mayumi Yoshida, M. Kikuchi, T. Nagao, H. Murakami, Tomoyuki Nomaki, A. Higurashi","doi":"10.2151/JMSJ.2018-039","DOIUrl":"https://doi.org/10.2151/JMSJ.2018-039","url":null,"abstract":"","PeriodicalId":17476,"journal":{"name":"Journal of the Meteorological Society of Japan","volume":"1 1","pages":"193-209"},"PeriodicalIF":3.1,"publicationDate":"2018-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2151/JMSJ.2018-039","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44513574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Misumi, Yasushi Uji, Y. Tobo, K. Miura, J. Uetake, Yoko Iwamoto, T. Maesaka, K. Iwanami
Continuous observations of cloud droplet size distributions (DSDs) in low-level stratiform clouds have been conducted at a height of 458 m from Tokyo Skytree (a 634-m-high broadcasting tower in Tokyo) using a cloud droplet spectrometer. In this report, the characteristics of cloud parameters related to the cloud DSD from June to December 2016 are presented. The mean cloud droplet number concentration ( N c ), average diameters, and effective diameters of cloud droplets in non-drizzling clouds were 213 cm −3 , 7.3 μm, and 9.5 μm, respectively, which are close to the reported values for continental stratiform clouds. The relationship between liquid water content (LWC; g m −3 ), N c (cm −3 ), and radar reflectivity ( Z ; mm 6 m −3 ) was estimated as LWC = 0.17 N c 0.50 Z 0.45 , with a coefficient of determination ( R 2 ) of 0.93. The observed cloud DSDs were well fitted by a lognormal distribution, and the average median diameter of the fitted DSD was 6.6 μm.
利用云滴谱仪在东京天空树(东京634米高的广播塔)458米高空连续观测了低空层状云的云滴大小分布。本报告给出了2016年6 - 12月与云DSD相关的云参数特征。非毛雨云的平均云滴数浓度(nc)为213 cm−3，平均云滴直径为7.3 μm，有效云滴直径为9.5 μm，与大陆层状云的数值接近。液态水含量(LWC;g m−3)，nc (cm−3)和雷达反射率(Z;mm 6 m−3)估计LWC = 0.17 N c 0.50 Z 0.45，决定系数(r2)为0.93。观测到的云DSD符合对数正态分布，拟合的DSD平均中位直径为6.6 μm。
{"title":"Characteristics of Droplet Size Distributions in Low-Level Stratiform Clouds Observed from Tokyo Skytree","authors":"R. Misumi, Yasushi Uji, Y. Tobo, K. Miura, J. Uetake, Yoko Iwamoto, T. Maesaka, K. Iwanami","doi":"10.2151/JMSJ.2018-040","DOIUrl":"https://doi.org/10.2151/JMSJ.2018-040","url":null,"abstract":"Continuous observations of cloud droplet size distributions (DSDs) in low-level stratiform clouds have been conducted at a height of 458 m from Tokyo Skytree (a 634-m-high broadcasting tower in Tokyo) using a cloud droplet spectrometer. In this report, the characteristics of cloud parameters related to the cloud DSD from June to December 2016 are presented. The mean cloud droplet number concentration ( N c ), average diameters, and effective diameters of cloud droplets in non-drizzling clouds were 213 cm −3 , 7.3 μm, and 9.5 μm, respectively, which are close to the reported values for continental stratiform clouds. The relationship between liquid water content (LWC; g m −3 ), N c (cm −3 ), and radar reflectivity ( Z ; mm 6 m −3 ) was estimated as LWC = 0.17 N c 0.50 Z 0.45 , with a coefficient of determination ( R 2 ) of 0.93. The observed cloud DSDs were well fitted by a lognormal distribution, and the average median diameter of the fitted DSD was 6.6 μm.","PeriodicalId":17476,"journal":{"name":"Journal of the Meteorological Society of Japan","volume":"96 1","pages":"405-413"},"PeriodicalIF":3.1,"publicationDate":"2018-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2151/JMSJ.2018-040","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43508097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
12 Convective initiation (CI) nowcasting often has a low probability of detection (POD) and 13 a high false-alarm ratio (FAR) at sub-tropical regions where the warm-rain processes often 14 occur. Using the high spatial- and temporal-resolution and multi-spectral data from the 15 Advanced Himawari Imager (AHI) on board Japanese new-generation geostationary satellite 16 Himawari-8, a stand-alone CI nowcasting algorithm is developed in this study. The 17 AHI-based CI algorithm utilizes the reflectance observations from channels 1 (0.47 μm ) and 7 18 (3.9 μm ), brightness temperature observations from infrared window channel 13 (10.4 μm ), the 19 dual-spectral differences between channels 10 (7.3 μm ) and 13, 13 and 15 (12.4 μm ), as well as 20 a tri-spectral combination of channels 11, 15 and 13, as CI predictors without relying on any 21 dynamic ancillary data (e.g., cloud type and atmospheric motion vector products). The 22 proposed AHI-based algorithm is applied to CI cases over Fujian province in the 23 Southeastern China. When validated by S-band radar observations, the CI algorithm 24 produced a POD as high as 93.33%, and a FAR as low as 33.33% for a CI case day that 25 occurred on 1 August 2015 over Northern Fujian. For over 216 CI events that occurred in a 26 three-month period from July to September 2015, the CI nowcasting lead time has a mean 27 value of ~64 minutes, with a longest lead time over 120 minutes. It is suggested that 28 false-alarm nowcasts that occur in the presence of capping inversion require further 29 investigation and algorithm enhancements.
{"title":"Summertime Convective Initiation Nowcasting over Southeastern China Based on Advanced Himawari Imager Observations","authors":"X. Zhuge, X. Zou","doi":"10.2151/JMSJ.2018-041","DOIUrl":"https://doi.org/10.2151/JMSJ.2018-041","url":null,"abstract":"12 Convective initiation (CI) nowcasting often has a low probability of detection (POD) and 13 a high false-alarm ratio (FAR) at sub-tropical regions where the warm-rain processes often 14 occur. Using the high spatial- and temporal-resolution and multi-spectral data from the 15 Advanced Himawari Imager (AHI) on board Japanese new-generation geostationary satellite 16 Himawari-8, a stand-alone CI nowcasting algorithm is developed in this study. The 17 AHI-based CI algorithm utilizes the reflectance observations from channels 1 (0.47 μm ) and 7 18 (3.9 μm ), brightness temperature observations from infrared window channel 13 (10.4 μm ), the 19 dual-spectral differences between channels 10 (7.3 μm ) and 13, 13 and 15 (12.4 μm ), as well as 20 a tri-spectral combination of channels 11, 15 and 13, as CI predictors without relying on any 21 dynamic ancillary data (e.g., cloud type and atmospheric motion vector products). The 22 proposed AHI-based algorithm is applied to CI cases over Fujian province in the 23 Southeastern China. When validated by S-band radar observations, the CI algorithm 24 produced a POD as high as 93.33%, and a FAR as low as 33.33% for a CI case day that 25 occurred on 1 August 2015 over Northern Fujian. For over 216 CI events that occurred in a 26 three-month period from July to September 2015, the CI nowcasting lead time has a mean 27 value of ~64 minutes, with a longest lead time over 120 minutes. It is suggested that 28 false-alarm nowcasts that occur in the presence of capping inversion require further 29 investigation and algorithm enhancements.","PeriodicalId":17476,"journal":{"name":"Journal of the Meteorological Society of Japan","volume":"96 1","pages":"337-353"},"PeriodicalIF":3.1,"publicationDate":"2018-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2151/JMSJ.2018-041","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43364563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Khatri, T. Hayasaka, H. Iwabuchi, T. Takamura, H. Irie, T. Nakajima
The present study implements long-term surface observed radiation data (pyranometer observed global flux and sky radiometer observed spectral zenith transmittance data) of multiple SKYNET sites to validate water cloud optical properties (cloud optical depth COD and effective radius Re) observed from space by MODIS onboard TERRA and AQUA satellites and AHI onboard Himawari-8 satellite. Despite some degrees of differences in COD and Re between MODIS and AHI, they both showed common features when validated using surface based global flux data as well as cloud properties retrieved from sky radiometer observed zenith transmittance data. In general, CODs from both satellite sensors are found to overestimated when clouds are optically thin. Among a number of factors (spatial and temporal variations of cloud, sensor and solar zenith angles), the solar zenith angle (SZA) is found to have an impact on COD difference between reflectance based satellite sensor and transmittance based sky radiometer. The Re values from the sky radiometer and satellite sensor are generally poorly correlated. The difference in Re between the sky radiometer and satellite sensor is negatively correlated with COD difference between them, which is likely due to the inherent influence of Re retrieval precision on COD retrieval and vice versa in transmittance based sky radiometer.
{"title":"Validation of MODIS and AHI Observed Water Cloud Properties Using Surface Radiation Data","authors":"P. Khatri, T. Hayasaka, H. Iwabuchi, T. Takamura, H. Irie, T. Nakajima","doi":"10.2151/JMSJ.2018-036","DOIUrl":"https://doi.org/10.2151/JMSJ.2018-036","url":null,"abstract":"The present study implements long-term surface observed radiation data (pyranometer observed global flux and sky radiometer observed spectral zenith transmittance data) of multiple SKYNET sites to validate water cloud optical properties (cloud optical depth COD and effective radius Re) observed from space by MODIS onboard TERRA and AQUA satellites and AHI onboard Himawari-8 satellite. Despite some degrees of differences in COD and Re between MODIS and AHI, they both showed common features when validated using surface based global flux data as well as cloud properties retrieved from sky radiometer observed zenith transmittance data. In general, CODs from both satellite sensors are found to overestimated when clouds are optically thin. Among a number of factors (spatial and temporal variations of cloud, sensor and solar zenith angles), the solar zenith angle (SZA) is found to have an impact on COD difference between reflectance based satellite sensor and transmittance based sky radiometer. The Re values from the sky radiometer and satellite sensor are generally poorly correlated. The difference in Re between the sky radiometer and satellite sensor is negatively correlated with COD difference between them, which is likely due to the inherent influence of Re retrieval precision on COD retrieval and vice versa in transmittance based sky radiometer.","PeriodicalId":17476,"journal":{"name":"Journal of the Meteorological Society of Japan","volume":"1 1","pages":"151-172"},"PeriodicalIF":3.1,"publicationDate":"2018-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2151/JMSJ.2018-036","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42737573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This article reports on the impacts of Himawari-8 Clear Sky Radiance (CSR) data assimilation in the global and mesoscale numerical weather prediction (NWP) systems of the Japan Meteorological Agency (JMA). Adoption of the Advanced Himawari Imager (AHI) on board JMA’s Himawari-8 and -9 satellites has enhanced observational capabilities in terms of spectral, horizontal, and temporal resolution. Improvements brought by the switchover from the Multi-functional Transport Satellite-2 (MTSAT-2) to the new-generation Himawari-8 satellite include an upgrade to the horizontal resolution of CSR data from 64 to 32 km and an increase in the number of available water vapor bands from one to three. CSR products are obtained every hour and distributed to the NWP community. The improved horizontal and spectral resolution of Himawari-8 CSR data provides new information on horizontal water vapor distribution and vertical profiles in data assimilation. In data assimilation experiments using JMA’s global NWP system, the assimilation of Himawari-8’s three water vapor bands significantly improved the tropospheric humidity field in analysis, especially in the lower troposphere, as compared to assimilation of the single MTSAT-2 water vapor channel. First-guess (FG) departure statistics for microwave humidity sounders indicated an improvement in the water vapor field, especially over Himawari-8 observation areas. Improved forecasting of tropospheric temperature, humidity, and wind fields for Himawari-8 observation areas was also seen. In data assimilation experiments using JMA’s mesoscale NWP system, a disastrous heavy precipitation event that took place in Japan’s Kanto-Tohoku region in 2015 was investigated. A single water vapor band of Himawari-8 CSR corresponding to MTSAT-2 was assimilated, resulting in enhanced contrast of the water vapor field between moist and dry areas, as well as a realistic representation of moist air flows from the ocean in analysis. The changes also improved mesoscale model heavy precipitation forecasts.
{"title":"Assimilation of Himawari-8 Clear Sky Radiance Data in JMA's Global and Mesoscale NWP Systems","authors":"M. Kazumori","doi":"10.2151/JMSJ.2018-037","DOIUrl":"https://doi.org/10.2151/JMSJ.2018-037","url":null,"abstract":"This article reports on the impacts of Himawari-8 Clear Sky Radiance (CSR) data assimilation in the global and mesoscale numerical weather prediction (NWP) systems of the Japan Meteorological Agency (JMA). Adoption of the Advanced Himawari Imager (AHI) on board JMA’s Himawari-8 and -9 satellites has enhanced observational capabilities in terms of spectral, horizontal, and temporal resolution. Improvements brought by the switchover from the Multi-functional Transport Satellite-2 (MTSAT-2) to the new-generation Himawari-8 satellite include an upgrade to the horizontal resolution of CSR data from 64 to 32 km and an increase in the number of available water vapor bands from one to three. CSR products are obtained every hour and distributed to the NWP community. The improved horizontal and spectral resolution of Himawari-8 CSR data provides new information on horizontal water vapor distribution and vertical profiles in data assimilation. In data assimilation experiments using JMA’s global NWP system, the assimilation of Himawari-8’s three water vapor bands significantly improved the tropospheric humidity field in analysis, especially in the lower troposphere, as compared to assimilation of the single MTSAT-2 water vapor channel. First-guess (FG) departure statistics for microwave humidity sounders indicated an improvement in the water vapor field, especially over Himawari-8 observation areas. Improved forecasting of tropospheric temperature, humidity, and wind fields for Himawari-8 observation areas was also seen. In data assimilation experiments using JMA’s mesoscale NWP system, a disastrous heavy precipitation event that took place in Japan’s Kanto-Tohoku region in 2015 was investigated. A single water vapor band of Himawari-8 CSR corresponding to MTSAT-2 was assimilated, resulting in enhanced contrast of the water vapor field between moist and dry areas, as well as a realistic representation of moist air flows from the ocean in analysis. The changes also improved mesoscale model heavy precipitation forecasts.","PeriodicalId":17476,"journal":{"name":"Journal of the Meteorological Society of Japan","volume":"96 1","pages":"173-192"},"PeriodicalIF":3.1,"publicationDate":"2018-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2151/JMSJ.2018-037","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42631884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The proposed study aims to examine the relation between the Tibetan Plateau (TP) thermal condition and El Niño and Southern Oscillation (ENSO). There were significant positive correlations between the snow water equivalent (SWE) over the TP from November to next April and sea surface temperature (SST) in the Eastern Equatorial Pacific (EEP) in November from 1987 to 2005. SST in EEP in November is most significantly cor related with the TP-SWE in next April, which suggests an accumulative effect of the ENSO on the TP snow cover. Although El Niño conditions could bring anomalous snowfall over the TP by generating a wave train en tering the North African-Asian jet, it is questionable if this impact could change the thermal condition over the TP. There was almost no significant negative correlation between the SWE and TP surface temperature (representing the TP thermal condition) in winter. This suggests that the TP thermal condition hardly varies with the anomalous snowfall caused by this ENSO impact, despite some cooling effect of snowfall during the El Niño phase. On the contrary, preceding El Niño conditions tended to be associated with increasing TP surface temperature in May and there were significant positive correlations between SWE in April and TP surface temperature in May and June. ENSO might play a part in affecting TP thermal condition in a way that is quite different from the previ ous research. A plausible mechanism based on the relation of ENSO-TP thermal condition has been proposed. The mechanism explained the direct and indirect effects of ENSO on the TP thermal condition and role that the seasonal progress can play in this relation. The issues about snow cover aging and the impact of global warming, among others, were also included in the mechanism.
{"title":"Impact of ENSO on the Thermal Condition over the Tibetan Plateau","authors":"Yafei Wang, Xiaoyu Xu","doi":"10.2151/JMSJ.2018-032","DOIUrl":"https://doi.org/10.2151/JMSJ.2018-032","url":null,"abstract":"The proposed study aims to examine the relation between the Tibetan Plateau (TP) thermal condition and El Niño and Southern Oscillation (ENSO). There were significant positive correlations between the snow water equivalent (SWE) over the TP from November to next April and sea surface temperature (SST) in the Eastern Equatorial Pacific (EEP) in November from 1987 to 2005. SST in EEP in November is most significantly cor related with the TP-SWE in next April, which suggests an accumulative effect of the ENSO on the TP snow cover. Although El Niño conditions could bring anomalous snowfall over the TP by generating a wave train en tering the North African-Asian jet, it is questionable if this impact could change the thermal condition over the TP. There was almost no significant negative correlation between the SWE and TP surface temperature (representing the TP thermal condition) in winter. This suggests that the TP thermal condition hardly varies with the anomalous snowfall caused by this ENSO impact, despite some cooling effect of snowfall during the El Niño phase. On the contrary, preceding El Niño conditions tended to be associated with increasing TP surface temperature in May and there were significant positive correlations between SWE in April and TP surface temperature in May and June. ENSO might play a part in affecting TP thermal condition in a way that is quite different from the previ ous research. A plausible mechanism based on the relation of ENSO-TP thermal condition has been proposed. The mechanism explained the direct and indirect effects of ENSO on the TP thermal condition and role that the seasonal progress can play in this relation. The issues about snow cover aging and the impact of global warming, among others, were also included in the mechanism.","PeriodicalId":17476,"journal":{"name":"Journal of the Meteorological Society of Japan","volume":"96 1","pages":"269-281"},"PeriodicalIF":3.1,"publicationDate":"2018-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2151/JMSJ.2018-032","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68294417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Okuyama, Masaya Takahashi, K. Date, K. Hosaka, Hidehiko Murata, T. Tabata, Ryoko Yoshino
The new geostationary (GEO) meteorological satellite of the Japan Meteorological Agency (JMA), Himawari-8, entered operation on 7 July 2015. Himawari-8 features the new 16-band Advanced Himawari Imager (AHI), whose spatial resolution and observation frequency are improved over those of its predecessor MTSAT-series satellites. These improvements will bring about unprecedented levels of performance in nowcasting services and short-range weather forecasting systems. In view of the essential nature of navigation and radiometric calibration in fully leveraging the imager’s potential, this study reports on the current status of calibration for the AHI. Image navigation is accurate to within 1 km, and band-to-band coregistration has also been validated. Infrared (IR) band calibration is accurate to within 0.2 K with no significant diurnal variation and is being validated using an approach developed under the Global Space-based Inter-Calibration System (GSICS) framework. Validation approaches are currently being tested for the visible and near-IR (NIR) bands. Two such approaches were compared and found to produce largely consistent results.
{"title":"Validation of Himawari-8/AHI Radiometric Calibration Based on Two Years of In-Orbit Data","authors":"A. Okuyama, Masaya Takahashi, K. Date, K. Hosaka, Hidehiko Murata, T. Tabata, Ryoko Yoshino","doi":"10.2151/JMSJ.2018-033","DOIUrl":"https://doi.org/10.2151/JMSJ.2018-033","url":null,"abstract":"The new geostationary (GEO) meteorological satellite of the Japan Meteorological Agency (JMA), Himawari-8, entered operation on 7 July 2015. Himawari-8 features the new 16-band Advanced Himawari Imager (AHI), whose spatial resolution and observation frequency are improved over those of its predecessor MTSAT-series satellites. These improvements will bring about unprecedented levels of performance in nowcasting services and short-range weather forecasting systems. In view of the essential nature of navigation and radiometric calibration in fully leveraging the imager’s potential, this study reports on the current status of calibration for the AHI. Image navigation is accurate to within 1 km, and band-to-band coregistration has also been validated. Infrared (IR) band calibration is accurate to within 0.2 K with no significant diurnal variation and is being validated using an approach developed under the Global Space-based Inter-Calibration System (GSICS) framework. Validation approaches are currently being tested for the visible and near-IR (NIR) bands. Two such approaches were compared and found to produce largely consistent results.","PeriodicalId":17476,"journal":{"name":"Journal of the Meteorological Society of Japan","volume":"1 1","pages":"91-109"},"PeriodicalIF":3.1,"publicationDate":"2018-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2151/JMSJ.2018-033","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42975710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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