Julia Kukulies

and 5 more

Frozen cloud particles are an important link in the hydrological cycle and significantly influence the Earth’s energy budget. Despite their important role, observational records constraining concentrations of atmospheric ice remain severely limited. While combined radar and lidar estimates from the CloudSat and CALIPSO missions offer over a decade of high-quality data on ice hydrometeor concentrations, these estimates remain sparse. In contrast, products derived from passive satellite sensors typically provide better spatiotemporal coverage but disagree with CloudSat-baed measurements.   To address these limitations, we present a novel climate data record of total ice water path (TIWP), the Chalmers Cloud Ice Climatology (CCIC). It spans 40 years, from 1983 to the present, covering latitudes from 70 degree South to 70 degree North. CCIC offers TIWP estimates at three-hourly resolution from 1983 and half-hourly resolution from 2000 onwards. We demonstrate the long-term stability of CCIC by directly comparing it with CloudSat/CALIPSO-based estimates over the entire mission lifetime. Additionally, we assess CCIC against other long-term TIWP records, revealing that CCIC yields most accurate TIWP estimates compared to CloudSat/CALIPSO-based reference estimates. An investigation of the regional trends in TIWP shows good agreement between four observational datasets and ERA5 for the most recent 20 years. However, the consistency decreases for 40-year trends.   The CCIC climate record closes the gap between existing long-term TIWP records and CloudSat/CALIPSO-based reference measurements. The estimates’ continuous coverage and demonstrated accuracy make it a valuable resource for lifecycle studies of storms and the analysis of fine-scale cloud features in a changing climate.