In this study, real-time analysis of products and information dissemination (RAPID), a web-based quick visualisation and analysis tool for INSAT satellite data on a real-time basis has been introduced for identification of pre-monsoon severe weather events. The tool introduces the next generation weather data access and advanced visualisation. The combination of channels using red-green-blue (RGB) composites of INSAT-3D satellite and its physical significant value contents are presented. The solar reflectance and brightness temperatures (BTs) are the major components of the RGB composite. The solar reflectance component of the shortwave thermal infrared (IR) (1.6 µm), visible (0.5 µm) and thermal IR channels (10.8 µm) representing the cloud microstructure is known as Day Microphysics (DMP) RGB and the BT differences between 10.8, 12.0 and 3.9 µm is known as Night Microphysics (NMP) RGB. The threshold technique has been developed separately for both the RGB products of the year 2015-2016 and 2016-2017 of March-June, prior to the event (1-3 hr) for the detection of the thunderstorms. A validation analysis was conducted using the Forecast Demonstration Project of Storm Bulletins for pre-monsoon weather systems prepared by the India Meteorological Department and RADAR observations, demonstrating that this approach is extremely useful in recognising the area of convection prior to the occurrence of the events by the RGB thresholds. The validation of these thresholds has been carried out for March-June 2017. Both the RGBs i.e., DMP and NMP have a reasonable agreement with the ground-based observations and RADAR data. This threshold technique yields a very good probability of thunderstorm detection more than 94% and 93% with acceptable false alarm conditions, less than 3% and 5% for DMP and NMP, respectively. Furthermore, the limitations of these RGB products are additionally highlighted, and the future extent of refinement of these products in perspective of a rapid scan strategy is proposed. The threshold techniques are found to be useful for nowcasting application and are being used operationally using the RAPID tool.
Abstract. The objectives of the
INSAT-3D satellite are to enhance the meteorological observations and to
monitor the Earth's surface for weather forecasting and disaster warning. One
of the weather-monitoring capabilities of the INSAT-3D sounder is the
estimation of water vapour in the atmosphere. The amount of water vapour
present in the atmospheric column is derived as the total precipitable water
(TPW) product from the infrared radiances measured by the INSAT-3D sounder.
The present study is based on TPW derived from INSAT-3D sounder, radiosonde
(RS) observations and the corresponding National Oceanic and Atmospheric
Administration (NOAA) satellite. To assess retrieval performances of INSAT-3D
sounder-derived TPW, RS TPW observations are considered for the validation
from May to September 2016 from 34 stations belonging to the India
Meteorological Department (IMD). The analysis is performed on daily, monthly,
and subdivisional bases over the Indian region. The comparison of INSAT-3D
TPW with RS TPW on daily and monthly bases shows that the root mean square
error (RMSE) and correlation coefficients (CC) are ∼8 mm and 0.8,
respectively. However, on subdivisional and overall scales, the RMSE found to
be in the range of 1 to 2 mm and CC was around 0.9 in comparison with RS and
NOAA. The spatial distribution of INSAT-3D TPW with actual rainfall
observation is also investigated. In general, INSAT-3D TPW corresponds well
with rainfall observation; however, it has found that heavy rainfall events
occur in the presence of high TPW values. In addition, the cases of
thunderstorm events were assessed using TPW from INSAT-3D and network of
Global Navigation Satellite System (GNSS) receiver. This shows the good
agreement between TPW from INSAT-3D and GNSS during the mesoscale activity.
The improvement in the estimation of TPW is carried out by applying the GSICS
calibration corrections (Global Space-based Inter-Calibration System) to the
radiances from infrared (IR) channels of the sounder, which is used by IMDPS
(INSAT Meteorological Data Processing System). The current TPW from INSAT-3D
satellite can be utilized operationally for weather monitoring and forecast
purposes. It can also offer substantial opportunities for improvement in
nowcasting studies.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.