Overview

The pan-European research infrastructure ACTRIS (The Aerosol, Clouds and Trace Gases Research Infrastructure) is aiming to produce high-quality data and information on short-lived atmospheric constituents and on the processes leading to the variability of these constituents in natural and controlled atmospheres. (https://www.actris.eu)

As part of ACTRIS the Karlsruhe Low Cloud Exploratory Platform (KLOCX) serves as a fully mobile ground-based observation system. It is mainly aimed to investigate processes involved in the development and dissipation of low-level clouds and fog using in-situ and remote sensing instruments.

Low-level clouds and fog impact our climate system but also human life. They reflect sunlight back into space, but also trap the Earth's thermal radiation. Up until now, one of the big questions in climate research is how strong these effects actually are. For humans, low-level clouds mostly pose a severe threat for aviation, sea and road traffic due to reduced visibility and they can prolong weather conditions favorable for reduced air quality.

With KLOCX, it will be possible to efficiently bundle the instrumentation needed for process studies directed to understand low-cloud and fog formation, persistence, and dissipation. Besides providing data for such process studies, the data collected will be available as ground truth to further improve satellite-based detection schemes of low clouds and fog.

Campaigns

ACTRIS ECCINT cloud in-situ intercomparison I (2022)

KLOCX participated with its ground-based fog and aerosol spectrometer in the 1st ACTRIS ECCINT cloud in-situ intercomparison for liquid water content (LWC), at the Sonnblick Observatory, Austria. The goal of the intercomparison was  to check and compare instrument performance for LWC and the impact of different setups and sampling techniques.

TEAMx Observational Campaign (2024/2025)

The Karlsruhe research platform KLOCX is participating in the international measurement campaign TEAMx (Multi-scale Transport and Exchange Processes – Programme and Experiment in the Atmosphere over Mountains) (https://www.teamx-programme.org) with a variety of state-of-the-art measuring instruments. The campaign, which focuses on exchange processes in the atmosphere over mountains, aims to improve our understanding of these processes and contribute to making weather and climate models more precise.

From September 25, 2024, to April 9, 2025, KLOCX will be part of TEAMx's winter campaign. The research focus will be on studying low stratiform clouds and fog. The primary goal of the measurements is to analyze the microphysical differences between the various life stages of low clouds and fog. This is crucial for improving satellite observation and analysis of fog and low clouds. The collected data will help to refine forecasting models and enable more accurate weather predictions.