Deep Convective Cloud Top Altitudes at High Temporal and Spatial Resolution

Abstract

We describe and validate a method of calculating convective cloud top altitudes and potential temperatures up to 50° latitude at high spatial (0.25°) and temporal (3 hr) resolution. The approach uses the statistics of the CloudSat cloud radar deep convective cloud classification product coupled with nighttime CALIOP lidar measurements to effectively “calibrate” the high frequency, high resolution global rainfall and brightness temperature data that is used to derive convective cloud top altitudes. Thus, our product agrees well with the statistics of the CloudSat/CALIOP convective cloud tops, especially in the tropics and over oceanic regions. Agreement is reasonable, but not as good, for land‐based convection. The estimated uncertainty in cloud top altitudes in our product is 0.5–1.0 km over land areas, with smaller uncertainties over the oceans. The diurnal cycle of the new convection data set is in good agreement with precipitation radar convective climatology.

Convective Impact on the Global Lower Stratospheric Water Vapor Budget

“…(2020). However, an important caveat is that these results are based on satellite‐derived convective cloud top altitude estimates with uncertainty of ∼0.5–1 km (Pfister et al., 2022). If the vertical extent and/or frequency of deep convective events are underestimated over some regions, and if we account for the potential mixing above the cloud tops (Dauhut et al., 2018; Lane, 2008), the impact of tropopause‐overshooting convection on lower stratospheric water vapor may indeed be much higher than that found in this study.…”

“…All data used in this study are publicly available at no charge and with unrestricted access. The satellite‐derived convective cloud top altitude data set (Pfister et al., 2022) is available at https://bocachica.arc.nasa.gov/nasaarc_cldalt/. The Aura MLS water vapor v5.0 data (Lambert et al., 2020; Livesey et al., 2020) are available through the NASA Goddard Earth Sciences Data and Information Center (GES DISC) at https://dx.doi.org/10.5067/Aura/MLS/DATA2508.…”

“…To accurately quantify the convective impact on the lower stratosphere on a global scale, we require observation-based estimates of the global convective cloud top altitudes at high temporal and spatial resolutions. We use the methodology described in Pfister et al (2022) with some modifications described below. Based on 3-hourly precipitation measurements from the 3B42 product (i.e., Tropical Rainfall Measuring Mission adjusted merged-infrared precipitation data; Huffman et al, 2007) and the superseding IMERG product (i.e., Integrated Multi-satellite Retrievals for GPM; Huffman et al, 2019), convective regions are first identified by searching for rainfall rates exceeding a threshold value of 0.9 mm hr −1 over land and 1.5 mm hr −1 over ocean; the different rainfall thresholds account for differences in the structure and microphysics (and thus rainfall rate) of convection over land and ocean.…”

A Lagrangian View of Seasonal Stratosphere‐Troposphere Exchange

“…Pfister et al. (2022), data is available at https://bocachica.arc.nasa.gov/nasaarc_cldalt/, data is public, unrestricted access. Software used for this study is IDL from L3Harris Geospatial licensed to the Mark Schoeberl and the Texas A&M University (https://www.l3harrisgeospatial.com/Software-Technology/IDL).…”

“…Cloud top data. Pfister et al (2022), data is available at https://bocachica.arc. nasa.gov/nasaarc_cldalt/, data is public, unrestricted access.…”