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Microwave Limb Sounder
The MLS RHI Product

Contact: William Read



Basic Information

RHi, relative humidity with respect to ice, is the ratio of (1) the amount of ice that an air parcel contains to (2) the maximum amount of ice that the parcel could contain in equilibrium at its current temperature. Relative humidity is generally expressed in percent.
A map of Relative Humidity
Sample relative humidity retrieval map



How it is part of MLS Science Objectives

One of the scientific objectives of MLS is studying climate change. MLS measurements of relative humidity along with temperature and cloud ice are important for improving our understanding climate processes.



How EOS MLS derives RHI

RHI is relative humidity with respect to ice. It is a derived product from the standard products of water vapor and terperature using the Goff-Gratch formula.

Another sample relative humidity retrieval map

(map from 2005d264)



Quick Product Information for data version v2.2

  • Swath Name: RHI
  • Vertical Resolution:6 - 8 km from 316-0.22 hPa
    12 - 16 km from 0.10-0.002 hPa
  • Useful Range: 316 - 0.002 hPa
  • DAAC Short Name: ML2RHI
  • Precision: 20-70% at 316-83 hPa
    15% from 68-0.46 hPa
    >20% at 0.22-0.002 hPa
  • Accuracy: TBD



Publications related to the MLS RHi data product

2007

  1. Read, W.G., A. Lambert, J. Bacmeister, R.E. Cofield, L.E. Christensen, D.T. Cuddy, W.H. Daffer, B.J. Drouin, E. Fetzer, L. Froidevaux, R. Fuller, R. Herman, R.F. Jarnot, J.H. Jiang, Y.B. Jiang, K. Kelly, B.W. Knosp, H.C. Pumphrey, K.H. Rosenlof, X. Sabounchi, M.L. Santee, M.J. Schwartz, W.V. Snyder, P.C. Stek, H. Su, L.L. Takacs, R.P. Thurstans, H. Vomel, P.A. Wagner, J.W. Waters, C.R. Webster, E.M. Weinstock, D.L. Wu, "Aura Microwave Limb Sounder upper tropospheric and lower stratospheric H2O and relative humidity with respect to ice validation", vol 112, pgs. D24S35, 2007. Reprint Supplemental

2006

  1. Cofield, R.E., P.C. Stek, "Design and field-of-view calibration of 114-660 GHz optics of the Earth Observing System Microwave Limb Sounder", vol 44, num no. 5, pgs. 1166-1181, 2006. Reprint
  2. Sherwood, S.C., E.R. Kursinski, W.G. Read, "A distribution law for free-troposphere relative humidity", vol 19, pgs. 6267-6277, 2006. Reprint

2005

  1. Waugh, D.W., "Impact of potential vorticity intrusions on subtropical upper tropospheric humidity", vol 110, pgs. D11305, 2005. Reprint

2004

  1. Jiang, J.H., B. Wang, K. Goya, K. Hocke, S.D. Eckermann, J. Ma, D.L. Wu, W.G. Read, "Geographical Distribution and Inter-Seasonal Variability of Tropical Deep Convection: UARS MLS Observations and Analyses", vol 109, pgs. D03111, 2004. Reprint Summary
  2. Read, W.G., D.L. Wu, J.W. Waters, H.C. Pumphrey, "A New 147-56 hPa Water Vapor Product from the UARS Microwave Limb Sounder", vol 109, pgs. D06111, 2004. Reprint
  3. Read, W.G., D.L. Wu, J.W. Waters, H.C. Pumphrey, "Dehydration in the Tropical Tropopause Layer: Implications from UARS MLS", vol 109, pgs. D06110, 2004. Reprint Summary

2003

  1. Salby, M., F. Sassi, P. Callaghan, W. Read, H. Pumphrey, "Fluctuations of Cloud, Humidity, and Thermal Structure near the Tropical Tropopause", vol 16, pgs. 3428-3446, 2003. Reprint

2002

  1. Folkins, I., K.K. Kelly, E.M. Weinstock, "A simple explanation for the increase in relative humidity between 11 and 14 km in the tropics", vol 107, num D23, pgs. 4736, 2002. Reprint
  2. Sassi, F., M. Salby, H.C. Pumphrey, W.G. Read, "Influence of the Madden-Julian Oscillation on upper tropospheric humidity", vol 107, num D23, pgs. 4681, 2002. Reprint Summary
  3. Spichtinger, P., K. Gierens, W. Read, "The statistical distribution law of relative humidity in the global tropopause region", vol 11, pgs. 83-88, 2002. Summary

2001

  1. Folkins, I., "Origin of Lapse Rate Changes in the Upper Tropical Tropopause", vol 59, pgs. 992-1005, 2001. Reprint
  2. Pawson, S., L. Takacs, A. Molod, S. Nebuda, M. Chen, W. Read, M. Fiorino, "The Tropical Upper Troposphere and Lower Stratosphere in the GEOS-2 GCM", vol 27, pgs. 1457-1465, 2001. Reprint
  3. Read, W.G., J.W. Waters, D.L. Wu, E.M. Stone, Z. Shippony, A.C. Smedley, C.C. Smallcomb, S. Oltmans, D. Kley, H G.J. Smit, J.L. Mergenthaler, M.K. Karki, "UARS Microwave Limb Sounder Upper Tropospheric Humidity Measurement: Method and Validation", vol 106, num D23, pgs. 32,207-35,258, 2001. Reprint Summary
  4. Sassi, F., M. Salby, W.G. Read, "Relationship between upper tropospheric humidity and deep convection", vol 106, num D15, pgs. 17,133-17,146, 2001. Reprint



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