References

ACPD

Atmospheric Chemistry and Physics Discussions

ACPD

1680-7375

Copernicus GmbH

Göttingen, Germany

10.5194/acpd-7-17741-2007

Measurement of the water vapour vertical profile and of the Earth's outgoing far infrared flux

Palchetti

¹ Bianchini

¹ Carli

¹ Cortesi

¹ Del Bianco

Istituto di Fisica Applicata "Nello Carrara" – Consiglio Nazionale delle Ricerche IFAC–CNR, Sesto Fiorentino, Firenze, 50019, Italy

10 12 2007

7 6 17741 17767

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Our understanding of global warming depends on the accuracy with which the atmospheric components that modulate the Earth's radiation budget are known. Many uncertainties still exist on the radiative effect of water in the different spectral regions, among which the far infrared where few observations have been made. An assessment is shown of the atmospheric outgoing flux obtained from a balloon-borne platform with wideband spectrally resolved nadir measurements at the top-of-atmosphere over the full spectral range, including the far infrared, from 100 to 1400 cm−1, made by a Fourier transform spectrometer with uncooled detectors. From these measurements, we retrieve 15 pieces of information about water vapour and temperature profiles, and surface temperature, with a precision of 5% for the mean water vapour profile and a major improvement of the upper troposphere-lower stratosphere knowledge. The retrieved atmospheric state makes it possible to calculate the emitted radiance as a function of the zenith angle and to determine the outgoing radiation flux, proving that spectrally resolved observations can be used to derive accurate information on the integrated flux. While the retrieved temperature is in good agreement with ECMWF analysis, the retrieved water vapour profile differs significantly, and, depending on time and location, the derived flux differs in the far infrared (0–600 cm−1) from that derived from ECMWF by 2–3.5 W/m2±0.4 W/m2. The observed discrepancy is larger than current estimates of radiative forcing due to CO2 increases since pre-industrial time. The error with which the flux is determined is caused mainly by calibration uncertainties while detector noise has a negligible effect, proving that uncooled detectors are adequate for top of the atmosphere radiometry.

References 1

Bianchini, G. and Palchetti, L.: REFIR-PAD level 1 data analysis and performance characterization, Atmos. Chem. Phys. Discuss., accepted, 2007.

Bianchini, G., Palchetti, L., and Carli, B.: A wide-band nadir-sounding spectroradiometer for the characterization of the Earth's outgoing long-wave radiation, 6361, p.63 610A, 2006.

Bianchini, G., Carli, B., Cortesi, U., Bianco, S D., Gai, M., and Palchetti, L.: Test of far infrared atmospheric spectroscopy using wide band ballon borne measurements of the upwelling radiance, J. Quant. Spectrosc. Rad., doi:10.1016/j.jqsrt.2007.11.010, 2007.

Carli, B., Bazzini, G., Castelli, E., Cecchi-Pestellini, C., Bianco, S D., Dinelli, B M., Gai, M., Magnani, L., Ridolfi, M., and Santurri, L.: MARC: A code for the retrieval of atmospheric parameters from millimeter-wave limb measurements, J. Quant. Spectrosc. Rad., 105, 476–491, 2007.

Chahine, M.: The hydrological cycle and its influence on climate, Nature, 359, 373–380, 1992.

Chou, C. and Neelin, J.: Cirrus Detrainment-Temperature Feedback, Geophys.\ Res. Lett., 26, 1295–1298, 1999.

Clerbaux, N., Dewitte, S., Gonzalez, L., Bertrand, C., Nicula, B., and Ipe, A.: Outgoing longwave flux estimation: improvement of angular modelling using spectral information, Remote Sens. Environ., 85, 389–395, 2003.

Clough, S A., Iacono, M J., and Moncet, J.-L.: Line-by-Line Calculations of Atmospheric Fluxes and Cooling Rates: Application to Water Vapor, J. Geophys. Res., 97, 15 761–15 785, 1992.

Clough, S A., Shepard, M W., Mlawer, E J., Delamere, J S., Iacono, M J., Cady-Pereira, K., Boukabara, S., and Brown, P D.: Atmospheric radiative transfer modelling: a summary of the AER codes, J. Quant. Spectrosc. Rad., 91, 233–244, 2005.

Cox, S.: Cirrus Clouds and the Climate, J. Atmos. Sci., 28, 1513–1515, 1971.

European-Commission: REFIR Radiation Explorer in the Far InfraRed, Tech. Rep. Final ENV4-CT6-0344, European Commission, Brussels, Belgium, 2000.

Del Genio, A. D., Yao, M.-S., Kovari, W., , and Lo, K. K.-W.: A prognostic cloud water parameterization for global climate models, J. Climate, 9, 270–304, 1996.

Gordon, I E., Rothman, L S., Gamache, R R., Jacquemart, D., Boone, C., Bernath, P F., Shephard, M W., Delamere, J S., and Clough, S A.: Current updates of the water-vapor line list in HITRAN:A new "Diet" for air-broadened half-widths, J. Quant. Spectrosc. Rad., 108, 389–402, 2007.

Harries, J E.: Atmospheric radiation and atmospheric humidity, Q. J. Roy.\ Meteor. Soc., 123, 2173–2186, 1997.

Harries, J E.: The Greenhouse Earth – A view from space, Q. J. Roy.\ Meteor. Soc., 122, 799–818, 1996.

Held, I M. and Soden, B J.: Water vapor feedback and global warming, Annu.\ Rev. Energ. Env., 25, 441–475, 2000.

Houghton, J.: The physics of atmospheres, Cambridge University Press, Cambridge, U.K., New York, 2002.

Lindzen, R.: Some Coolness Concerning Global Warming, Bull. Amer. Meteor.\ Soc., 71, 288–299, 1990.

Liou, K.-N.: Influence of cirrus clouds on weather and climate processes, a global perspective, Mon. Weath. Rev., 114, 1167–1199, 1986.

Mertens, C J.: Feasibility of retrieving upper tropospheric water vapor from observations of far-infrared radiation, 4485, pp.191–201, SPIE, 2002.

Niro, F., Jucks, K., and Hartmann, J M.: Spectra calculations in central and wing regions of CO2 IR bands. IV: software and database for the computation of atmospheric spectra, J. Quant. Spectrosc. Rad., 95, 469–481, 2005a.

Niro, F., \textnormal Von Clarmann, T., Jucks, K., and Hartmann, J M.: Spectra calculations in central and wing regions of CO2 IR bands between 10 and 20 μm. III: atmospheric emission spectra, J. Quant. Spectrosc.\ Rad., 90, 61–76, 2005b.

Palchetti, L., Bianchini, G., Castagnoli, F., Carli, B., Serio, C., Esposito, F., Cuomo, V., Rizzi, R., and Maestri, T.: The breadboard of the Fourier transform spectrometer for the Radiation Explorer in the Far Infrared (REFIR) atmospheric mission, Appl. Opt., 44, 2870–2878, 2005.

Palchetti, L., Belotti, C., Bianchini, G., Castagnoli, F., Carli, B., Cortesi, U., Pellegrini, M., Camy-Peyret, C., Jeseck, P., , and Té, Y.: Technical note: First spectral measurement of the Earth's upwelling emission using an uncooled wideband Fourier transform spectrometer, Atmos. Chem. Phys., 6, 5025–5030, 2006.

Pierrehumbert, R.: The hydrologic cycle in deep-time climate problems, Nature, 419, 191–198, 2002.

Randall, D., Wood, R., and et~al.: Climate Models and Their Evaluation, chap 8, IPCC WG1 AR4 Final Report, 2007.

Randall, D A., Harshvardhan, Dazlich, D A., and Corsetti, T G.: Interactions among Radiation, Convection, and Large-Scale Dynamics in a General Circulation Model, J. Atmos. Sci., 47, 1943–1970, 1989.

Remedios, J J.: Extreme atmospheric constituent profiles for MIPAS, 2, pp. 779–783, 96, 1999.

Rizzi, R., Palchetti, L., Carli, B., Bonsignori, R., Harries, J E., Leotin, J., Peskett, S C., Serio, C., and Sutera, A.: Feasibility of the spaceborne radiation explorer in the far infrared (REFIR), 4485, pp. 202–209, SPIE, prefixhttp://link.aip.org/link/?PSI/4485/202/1, 2002.

Rodgers, C D.: Inverse Methods for Atmospheric Sounding: Theory and Practice, World Scientific, Singapore, New Jersey, London, Hong Kong, 2000.

Rothman, L S., Jacquemart, D., Barbe, A., Benner, D C., Birk, M., Brown, L R., Carleer, M R., and Wagner, .G.: The HITRAN 2004 molecular spectroscopic database, J. Quant. Spectrosc. Rad., 96, 139–204, 2005.

Sinha, A. and Harries, J E.: Water vapor and greenhouse trapping: the role of far infrared absorption, Geophys. Res. Lett., 22, 2147–2150, 1995.

Stephens, G., Tsay, S., Stackhouse, P J., and Flatau, P.: The Relevance of the Microphysical and Radiative Properties of Cirrus Clouds to Climate and Climatic Feedback, J. Atmos. Sci., 47, 1742–1754, 1990.

Stuber, N., Ponater, M., and Sausen, R.: Why radiative forcing might fail as a predictor of climate change, Clim. Dynam., 2005.

Suttles, J T., Wielicki, B A., and Vemury, S.: Top-of-Atmosphere Radiative Fluxes: Validation of ERBE Scanner Inversion Algorithm Using Nimbus-7 ERB Data, J. Appl. Meteor., 31, 784–796, 1992.

Tobin, D C., Best, F A., Brown, P D., Clough, S A., Dedecker, R G., Ellingson, R G., Garcia, R K., Howell, H B., Knuteson, R O., Mlawer, E J., Revercomb, H E., Short, J F., van Delst, P. F W., and Walden, V P.: Downwelling spectral radiance observations at the SHEBA ice station: Water vapor continuum measurements from 17 to 26 μm, J. Geophys. Res., 104, 2081–2092, 1999.

\textnormal Van Vleck, J H. and Weisskopf, V F.: On the Shape of Collision-Broadened Lines, Revs. Mod. Phys., 17, 227–236, 1945.

Wielicki, B A., Barkstrom, B R., Harrison, E F., Lee, R B., \textnormal Louis~Smith, G., and Cooper, J E.: Clouds and the Earth's Radiant Energy System (CERES): An Earth Observing System Experiment, Bull. Amer. Meteor.\ Soc., 77, 853–868, 1996.