5:15 PM - 6:45 PM
[ACG36-P21] Analysis of long-term trends in global precipitation products
Keywords:Precipitation observation, Spaceborne precipitation radar, long term trend
Global precipitation products have been provided by the GPCP project for more than 40 years since 1979 which is based on the geostationary meteorological satellite observation. Since then, a combined data set of microwave radiometer and geostationary meteorological satellite has been available for about 25 years since 1998 (GSMaP, IMERG), after the launch of TRMM satellite. Now it has become possible to implement the analysis of long-term trends over 20 years. In this study, the long-term trend of precipitation mainly from the GSMaP are analyzed and is compared with those of the water equivalent thickness observed by GRACE and GRACE FO, which have more than 20 years of global data, and with those of the radiation budget at TOA observed by CERES.
The data used in this study are GSMaP Gauge (V8) precipitation, surface precipitation from TRMM and GPM Ku-band radar, GPCP (V3.2) precipitation, GRACE, and CERES EBAF monthly average products. The analysis examines the long-term trends of each product and the correlations between those trends for overall (2002 to 2022, total 252 months) and monthly data.
The analysis result shows that both GSMaP and GPCP shows significant trends in the tropical Pacific. In particular, the trend in the Eastern Pacific is similar to the results obtained in CERES (e.g. Loeb et al., 2022). This result is also confirmed by precipitation radar (TRMM/PR and GPM/KuPR). On the other hand, significant trends can be seen at high latitudes either of GSMaP or GPCP. The monthly trend shows that the trend in the Eastern Pacific appeared from October to December. Further monthly trends showed significant trends near the maritime continent in December, in the Indian Ocean in May, in the South Pacific in June and November, etc. Although this analysis does not show a clear agreement between GRACE and precipitation products, further analysis that takes into account time lags and other factors is necessary.
The data used in this study are GSMaP Gauge (V8) precipitation, surface precipitation from TRMM and GPM Ku-band radar, GPCP (V3.2) precipitation, GRACE, and CERES EBAF monthly average products. The analysis examines the long-term trends of each product and the correlations between those trends for overall (2002 to 2022, total 252 months) and monthly data.
The analysis result shows that both GSMaP and GPCP shows significant trends in the tropical Pacific. In particular, the trend in the Eastern Pacific is similar to the results obtained in CERES (e.g. Loeb et al., 2022). This result is also confirmed by precipitation radar (TRMM/PR and GPM/KuPR). On the other hand, significant trends can be seen at high latitudes either of GSMaP or GPCP. The monthly trend shows that the trend in the Eastern Pacific appeared from October to December. Further monthly trends showed significant trends near the maritime continent in December, in the Indian Ocean in May, in the South Pacific in June and November, etc. Although this analysis does not show a clear agreement between GRACE and precipitation products, further analysis that takes into account time lags and other factors is necessary.