Articles | Volume 9, issue 7
Atmos. Meas. Tech., 9, 2845–2875, 2016
Atmos. Meas. Tech., 9, 2845–2875, 2016
Review article
07 Jul 2016
Review article | 07 Jul 2016

Accomplishments of the MUSICA project to provide accurate, long-term, global and high-resolution observations of tropospheric {H2O,δD} pairs – a review

Matthias Schneider1, Andreas Wiegele1, Sabine Barthlott1, Yenny González2,3,a, Emanuel Christner1, Christoph Dyroff1,b, Omaira E. García2, Frank Hase1, Thomas Blumenstock1, Eliezer Sepúlveda2, Gizaw Mengistu Tsidu4,5, Samuel Takele Kenea4,c, Sergio Rodríguez2, and Javier Andrey6,d Matthias Schneider et al.
  • 1Institute of Meteorology and Climate Research (IMK-ASF), Karlsruhe Institute of Technology, Karlsruhe, Germany
  • 2Izaña Atmospheric Research Center, Agencia Estatal de Meteorología (AEMET), Santa Cruz de Tenerife, Spain
  • 3Sieltec Canarias, S.L., Hábitat 2, 38204, San Cristóbal de La Laguna, Santa Cruz de Tenerife, Spain
  • 4Department of Physics, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia
  • 5Botswana International University of Technology and Science (BIUST) Priv. Bag 16, Palapye, Botswana
  • 6Area de Investigación e Instrumentación Atmosférica, INTA, Torrejón de Ardoz, Spain
  • anow at: Dept. of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139-4307, USA
  • bnow at: Aerodyne Research Inc., 45 Manning Road, Billerica, MA 01821, USA
  • cnow at: Department of Physics, Samara University, P.O. Box 132, Samara, Ethiopia
  • dnow at: CNRM-GAME, Météo France and CNRS, Toulouse, France

Abstract. In the lower/middle troposphere, {H2O,δD} pairs are good proxies for moisture pathways; however, their observation, in particular when using remote sensing techniques, is challenging. The project MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water) addresses this challenge by integrating the remote sensing with in situ measurement techniques. The aim is to retrieve calibrated tropospheric {H2O,δD} pairs from the middle infrared spectra measured from ground by FTIR (Fourier transform infrared) spectrometers of the NDACC (Network for the Detection of Atmospheric Composition Change) and the thermal nadir spectra measured by IASI (Infrared Atmospheric Sounding Interferometer) aboard the MetOp satellites. In this paper, we present the final MUSICA products, and discuss the characteristics and potential of the NDACC/FTIR and MetOp/IASI {H2O,δD} data pairs.

First, we briefly resume the particularities of an {H2O,δD} pair retrieval. Second, we show that the remote sensing data of the final product version are absolutely calibrated with respect to H2O and δD in situ profile references measured in the subtropics, between 0 and 7 km. Third, we reveal that the {H2O,δD} pair distributions obtained from the different remote sensors are consistent and allow distinct lower/middle tropospheric moisture pathways to be identified in agreement with multi-year in situ references. Fourth, we document the possibilities of the NDACC/FTIR instruments for climatological studies (due to long-term monitoring) and of the MetOp/IASI sensors for observing diurnal signals on a quasi-global scale and with high horizontal resolution. Fifth, we discuss the risk of misinterpreting {H2O,δD} pair distributions due to incomplete processing of the remote sensing products.

Short summary
Tropospheric {H2O,δD} pairs can be observed by remote sensing techniques, but the data quality strongly depends on a comprehensive consideration of the complex nature and a careful calibration of the remote sensing data pairs. This paper reviews the quality assurance/documentation activities of the MUSICA project and demonstrates that MUSICA’s ground-based FTIR and space-based IASI {H2O,δD} pair products are accurate and can be generated at a global scale with high resolution and for long periods.