MMValRo

Abstract:

Within the MMValRO project, the Wegener Center will develop and provide long-term radio occultation (RO) validation data, which will be used in the long-loop monitoring of trends related to both spaceborne instrument and climate system variability, routine validation of atmospheric satellite products, validation of geophysical retrieval algorithms, bridging between temporally separated space missions, as well as scientific evaluation of atmospheric processes. The project will ensure the collection of correlative RO measurements suitable for in-depth examination of tropospheric and stratospheric profiles retrieved from (ESA) satellite observations.

This undertaking is highly worthwhile since the unique combination of global coverage, high accuracy, long-term stability, and all weather capability makes the validation with RO measurements preferable to other methods. The currently available RO receiver constellation provides a combined total of up to about 2500 profiles per day. With the further extension of the Global Navigation Satellite System (GNSS), e.g., by the upcoming Galileo system, this number will further increase.

In the frame of the MMValRO project, a long-term database of temperature, humidity, pressure, density, and refractivity, as a function of mean-sea-level altitude, will be established, covering in particular the thermodynamic state of the upper troposphere/lower stratosphere region. The correlative RO data provided during the project will be co-located with the comparable ESA mission datasets from the Envisat atmospheric instruments MIPAS and GOMOS, as well as the main ground-based validation sites as defined in the TASTE and EQUAL projects related to Envisat. Correlative data for specific campaigns will also be provided on ESA demand. The correlative data will be provided to a Cal/Val repository of ESA, which will provide the Cal/Val and science community a direct access to these data (Envisat Validation Data Centre, hosted by NILU, Kjeller, Norway).

Furthermore, the Wegener Center will validate the selected ESA satellite data (from MIPAS and GOMOS) against the correlative RO data used as reference, in order to derive estimates of the systematic and random errors and their changes in time. Also specific validation support to ESA algorithm developments and other ad-hoc requests will be provided on ESA demand. Support and advice regarding ESA validation strategies, both multi-mission and mission-specific for ESA missions, will be provided on demand as well.