- Airborne Instrumentation
ICON, the In-situ Capability for O2/N2 measurements from airborne platforms, uses VUV absorption to accurately measure atmospheric oxygen based on the development by Britt Stephens from NCAR. It is currently in the laboratory evaluation phase.
We are developing a prototype CO2 instrument with high precision and fast response for airborne measurements. Future application ist he integration onboard commercial airliners for long term measurements within the IAGOS project. Currently we are experimenting with an NDIR instrument as well as with approaches based on laser spectroscopy.
A prototype of a flask sampling system designed to collect samples that can be analyzed for CO2, 13CO2, C18O2, CO, CH4, SF6, H2, N2O and the ratio O2/N2. This sampler has been extensively validated in the laboratory (see Diploma thesis by Angelika Mennecke). The instrument was supposed to be used in the YAK project, but unfortunately, due to import and export resrictions for flasks, the sampler could not be deployed so far.
- MetAir AG Research Airplane
For atmospheric experiments we use the MetAir Dimo (link), a fully equipped research platform. The aircraft is hired on a campaign basis. Recently, we have used the aircraft within CERES
- Modelling tools
The Stochastic Time Inverted Lagrangian Transport is a fast tool to retrieve the tracer transport adjoint (sensitivity of atmospheric tracer mixing ratio measured at receptor point with respect to upstream variations in surface fluxes), based on forecasted or analyzed winds including a stochastic turbulence parameterization. In forecast mode it is used for flight planning purposes. STILT has been turned into a prototype framework to assimilate information from multiple data streams for retrieving regional fluxes. STILT is coupled to boundary conditions such as fossil fuel inventories, biospheric fluxes, and a data based lateral boundary condition for CO2 and CO.
The Weather Research and Forecasting System
is a next-generation forecasting model, currently being developed by a large comunity headed by NCAR
and NOAA. We have coupled WRF to the diagnostic biosphere model VPRM and to fossil fuel CO2
emissions. We use this modelling system to simulate tracer transport in the vicinity of observational sites such as the tall towers in order to better understand the measurements. Future applications to mesoscale inverse modelling to retrieve surface fluxes from concentrations will be realized by coupling WRF with STILT.
The Vegetation Photosynthesis and Respiration Model is a simple diagnostic model to simulate biosphere-atmosphere exchange of CO2
based on the MODIS indices EVI (enhanced vegetation index) and LSWI (land surface water index) as well as downward shortwave radiation and temperature. It was developed by Pathmathevan Mahadevan at Harvard University
, based on the work of Xiangming Xiao from UNH
. We use the VPRM to provide high temporal and spatial resolution exchange fluxes, that are consistent with Eddy flux measurements, to atmospheric transport models (STILT, WRF) as a priori informations for inversions.