In-situ measurements are essential for in-depth process studies. Further do they provide important references for the evaluation of remote sensing observations and numerical models. This session invites contributions that showcase innovative in-situ observation approaches and their application for an advanced understanding of urban climate processes at different scales.

We encourage submissions that demonstrate the value of in-situ observations for addressing specific research questions, validating modeling results, and informing urban climate adaptation and mitigation strategies.

Relevant aspects may include:
• Data integration and analysis: Development of methods for integrating in-situ data with remote sensing observations and numerical models to improve our understanding of urban climate dynamics.
• Other New/Innovative observational techniques or approaches that enhance the understanding of urban climate dynamics.

The session is organised in three chapters
a) Urban boundary layer processes
• Atmospheric profiling: Profile observations of the urban atmosphere (and boundary layer) using in-situ methods (e.g. radiosondes, tethered balloons, UAS)
• Atmospheric remote sensing on ground-based (or also spaceborne) platforms, such as Doppler wind lidars, automatic lidars and ceilometers, differential absorption lidars, microwave radiometers, or infrared radiometers.

b) Microclimates with a focus on the urban canopy layer
• Meteorological stations: Deployment and operation of meteorological stations to measure temperature, humidity, wind speed and direction, precipitation, and other atmospheric variables.
• Monitoring of urban green, blue, and brown infrastructures to evaluate their contribution to mitigating urban heat risks.

c) Surface-atmosphere interactions mostly at local and neighbourbood scales
• Eddy covariance flux towers: Utilization of eddy covariance techniques to quantify the exchange of heat, moisture, or momentum between urban surfaces and the atmosphere.