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Tropical "tape recorder" signal in MLS H2O data
adapted from Mote et al. J. Geophys. Res., vol. 101, 3989-4006 [1996]


time series of UARS MLS H2O tape recorder from 1991-1994

Time-height sections of MLS water vapor mixing ratio shown as the deviation (in parts per million by volume) from the time-mean profile, between 12oS and 12oN latitudes.

The results shown in this figure are from MLS data specially-processed by H.C.Pumphrey with non-linear iterative retrieval algorithms producing values for every standard UARS pressure surface (as opposed to every other surface for the Version 3 and Version 4 production algorithms). The results of this procedure should be regarded as prelimary because (1) they use MLS version 3 temperature and tangent pressure values which have known minor problems, and (2) detailed error analyses have not yet been performed for it.

The data clearly suggests the upward advection of successive minima and maxima in H2O, first discovered in MLS Version 3 H2O data by Mote et al [Geophys. Res. Lett. vol. 22, 1093-1096, 1996] whose analyses showed


The specially-preocessed data shown here indicate the transit time from 100 hPa to 46 hPa is 6 months or more (altitudes below 46 hPa are beyond the range of the standard Version 3 and Version 4 MLS retrievals).

See Mote et al. [J. Geophys. Res. vol. 101, 3989-4006, 1996] for further discussing of these and related data, and their analyses, including implications for vertical diffusion and mixing in from mid-latitudes.

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