Estimation of extreme daily precipitation thermodynamic scaling using gridded satellite precipitation products over tropical land

Abstract

This study explores the tropical land distribution of precipitation and its extremes focusing on the daily 1°×1°scale. A common period of 5-year over the tropical belt (30°s-30°n) corresponding to more than 39 million data points, is used to highlight the robust (and non-robust) observed features. A set of 10 observational products is analyzed ranging from satellite only to rain gauges only products and various blended intermediates as well as a sub ensemble of satellite-based products relying upon microwave observations. Overall, the various datasets show a small diversity of response as far as tropical land mean precipitation is concerned. When sorted by surface temperature, the spread in mean rainfall is also well below 10% over a large span of the surface temperature regime. The consistency between the surface temperature and the extreme precipitation is further investigated by computing the thermodynamic scaling of daily precipitation extreme with surface temperature. The wet days' 99.9th and 99th percentiles are considered and corresponds to 'extreme' extremes (∼110 mm d −1 ) and 'moderate' extremes (∼60 mm d −1 ), respectively. The analysis reveals three regimes over the 287-305 K 2 m temperature range. In the cold regime, 287-293 K, extremes exhibit no dependence to surface temperature while in the warm regime, 299-305 K, the extremes decrease with temperature as identified in previous studies. Over the 293-299 K regime, the scaling of the sub ensemble of satellite products is ∼5.2 K/% for the 'extremes' extremes and 5.0% for the 'moderate' extremes, and is robust throughout the sub ensemble. This analysis fills the regional gap of previous conventional data based studies and further confirms the Clausius-Clapeyron theoretical expectation for the tropical land regions.

Diverse estimates of annual maxima daily precipitation in 22 state-of-the-art quasi-global land observation datasets

“…On the contrary, prcptot values compare much better across the 22 datasets. We find a better comparison between the datasets for the median and 25th and 75th percentiles of the global distributions of prcptot (vertical lines in figure 1), in agreement with the findings of Alexander et al (2020) and Roca (2019b).…”

Intercomparison of annual precipitation indices and extremes over global land areas from in situ, space-based and reanalysis products

“…This is particularly evident in the intensity-based metrics such as Rx1day ( figure S7), with the wettest day in GPCC_FDD_2018 being around 40% wetter on average than the other in situ products (see climatological global averages inserted in figure S7). Differences are clearest in the tropics as also highlighted in Bador et al (2020) and Roca (2019). Indeed GPCC_FDD_2018 has the largest land-based daily precipitation intensity (9.3 mm d −1 ) of any other product ( figure S9), the other products ranging from 5.5 mm d −1 (CHIRP_v2) to 9.0 mm d −1 (3B42_IR_v7.0) on average over the 2001-2013 period.…”

Earth's water reservoirs in a changing climate

“…A set of 10 observational products ranging from satellite 30°S-30°N) land for the period 2012-2016. The colours correspond to various precipitation datasets listed on the right and described further in [122]. (b) The value of the 99.9th and 99th percentiles of the 1 × 1 daily accumulated tropical precipitation function of the 2 m daily temperature for a sub-set of the ensemble the observational products of (a).…”