Low clouds over tropical oceans have a cooling impact on the Earth's radiation budget. They strongly reflect the incoming solar radiation (high albedo) and slightly reduce the terrestrial emission (Scott et al., 2020). They also impact the temperature and moisture of the marine boundary layer (Bretherton et al., 2013) and are crucial in modulating the air-sea interactions that influence the sea surface temperature (SST) patterns (Yuan et al., 2018). Stratocumulus clouds prevail where free tropospheric subsidence reinforces the atmospheric boundary layer (ABL) stability, while shallow cumuliform clouds develop where subsidence and ABL inversion are weaker, typically over warmer surfaces with a deeper ABL (Mieslinger et al., 2019). Bony and Dufresne (2005) identify such clouds as the largest source of uncertainty in climate model predictions. Most climate models cannot realistically simulate low cloud processes and strongly diverge in the feedback to global warming (Zelinka et al., 2020). Recent observational studies show that in response to surface warming,
The Neckar Valley and the Swabian Jura in southwest Germany comprise a hotspot for severe convective storms, causing tens of millions of euros in damage each year. Possible reasons for the high frequency of thunderstorms and the associated event chain across compartments were investigated in detail during the hydro-meteorological field campaign Swabian MOSES carried out between May and September 2021. Researchers from various disciplines established more than 25 temporary ground-based stations equipped with state-of-the-art in situ and remote sensing observation systems, such as lidars, dual-polarization X- and C-band Doppler weather radars, radiosondes including stratospheric balloons, an aerosol cloud chamber, masts to measure vertical fluxes, autosamplers for water probes in rivers, and networks of disdrometers, soil moisture, and hail sensors. These fixed-site observations were supplemented by mobile observation systems, such as a research aircraft with scanning Doppler lidar, a cosmic ray neutron sensing rover, and a storm chasing team launching swarmsondes in the vicinity of hailstorms. Seven Intensive Observation Periods (IOPs) were conducted on a total of 21 operating days. An exceptionally high number of convective events, including both unorganized and organized thunderstorms such as multicells or supercells, occurred during the study period. This paper gives an overview of the Swabian MOSES (Modular Observation Solutions for Earth Systems) field campaign, briefly describes the observation strategy, and presents observational highlights for two IOPs.
Abstract. Important topics in land–atmosphere (L–A) feedback research are water and energy balances and heterogeneities of fluxes at the land surface and in the atmospheric boundary layer (ABL). To target these questions, the Land–Atmosphere Feedback Observatory (LAFO) has been installed in southwestern Germany. The instrumentation allows comprehensive and high-resolution measurements from the bedrock to the lower free troposphere. Grouped into three components, atmosphere, soil and land surface, and vegetation, the LAFO observation strategy aims for simultaneous measurements in all three compartments. For this purpose the LAFO sensor synergy contains lidar systems to measure the atmospheric key variables of humidity, temperature and wind. At the land surface, eddy covariance stations are operated to record the energy distribution of radiation, sensible, latent and ground heat fluxes. Together with a water and temperature sensor network, the soil water content and temperature are monitored in the agricultural investigation area. As for vegetation, crop height, leaf area index and phenological growth stage values are registered. The observations in LAFO are organized into operational measurements and intensive observation periods (IOPs). Operational measurements aim for long time series datasets to investigate statistics, and we present as an example the correlation between mixing layer height and surface fluxes. The potential of IOPs is demonstrated with a 24 h case study using dynamic and thermodynamic profiles with lidar and a surface layer observation that uses the scanning differential absorption lidar to relate atmospheric humidity patterns to soil water structures. Both IOPs and long-term observations will provide new insight into exchange processes and their statistics for improving the representation of L–A feedbacks in climate and numerical weather prediction models. The lidar component in particular will support the investigation of coupling to the atmosphere.
Abstract. Important topics in Land-Atmosphere (L-A) feedback research are water and energy balances and heterogeneities of fluxes at the land-surface and in the atmospheric booundary layer. To target these questions, the Land-Atmosphere Feedback Observatory (LAFO) has been installed in Southwest Germany. The instrumentation allows comprehensive and high-resolution measurements from the bedrock to the lower free troposphere. Grouped in three components: atmosphere, soil and land-surface and vegetation, the LAFO observation strategy aims for simultaneous measurements in all three compartments. For that the LAFO sensor synergy contains lidar systems to measure the atmospheric key variables humidity, temperature and wind. At the land-surface eddy covariance stations operated to record the energy distribution of radiation, sensible, latent and ground heat fluxes. With a water and temperature sensor network the soil water and temperature is monitored in the agricultural investigation area. The observations in LAFO are organized in operational measurements and intensive observation periods (IOPs). Operational measurements aim for long timeseries dataset to investigate statistics as we present as example the correlation between mixing layer height and surface fluxes. The potential of IOPs is demonstrated with a 24 hour case study with dynamic and thermodynamic profiles with lidar as well as a surface layer observation with the scanning differential absorption lidar to relate atmospheric humidity patterns to soil water structures. Both long-term observations and IOPs are important for improving the representation of L-A feedbacks in climate and numerical weather prediction models.
<p>Investigating the dynamics of the atmospheric boundary layer (ABL) is essential for studies of air quality, the energy and water cycles and for the improvement of weather and climate models. During daytime in convective conditions,<strong> </strong>the convective boundary layer (CBL) is formed. Here, we present our approach of how to continuously study CBL characteristics with an improved algorithm including fuzzy logic. The Land-Atmosphere Feedback Observatory (LAFO) of University of Hohenheim consists of two Doppler lidars, a Doppler Cloud Radar, the Atmospheric Raman Temperature and Humidity Sounder (ARTHUS), and Eddy covariance stations. These are excellent tools for observing high resolution atmospheric wind profiles, clouds and precipitation events, as well as thermodynamic profiles and surface fluxes. The data are collected at LAFO by operating continuously two Doppler lidars, one in vertical and one in six-beam scanning mode, to obtain vertical and horizontal wind profiles. Both Doppler lidars are operated with resolutions of 1 s and 30 m. The six-beam staring Doppler lidar is used for obtaining time series of turbulent kinetic energy (TKE), momentum flux, TKE dissipation rate and horizontal wind profiles statistics. The vertically staring Doppler lidar is used to compute statistics of higher-order moments of vertical wind fluctuations, the CBL height, and cloud base height. With these data, the land-atmosphere coupling processes and the associated nonlinear feedbacks are investigated as well as their impact on the turbulent structure of the CBL.</p> <p>We will present analyses of two three-month periods covering different weather conditions: 1 May to 31 July 2021 and 2022.</p>
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