<title>Specular scattering and crystal dynamics in cirrus clouds</title>

The lattice dynamics of cuprous halides have been thoroughly investigated by means of an 8-parameter bond-bending force model (BBFM), recently developed and applied successfully to study phonons in various II–VI and III–V compound semiconductors having zinc-blende (ZB) structure. The application of BBFM is made to calculate the phonon dispersion relations, phonon density of states, and temperature variation of the Debye characteristic temperature [Formula: see text] of CuCl, CuBr, and CuI. The room-temperature neutron scattering measurements for phonon dispersion curves along three principal symmetry directions and calorimetric experimental data for the Debye characteristic temperature have been used to check the validity of BBFM for the three crystals. The overall good agreement between theoretical and experimental results supports its use as an appropriate model for the dynamical description of ZB crystals.

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Correction Method for RS80-A Humicap Humidity Profiles and Their Validation by Lidar Backscattering Profiles in Tropical Cirrus Clouds

Journal of Atmospheric and Oceanic Technology ◽

10.1175/jtech-1684.1 ◽

2005 ◽

Vol 22 (1) ◽

pp. 18-29 ◽

Cited By ~ 27

Author(s):

Ulrich Leiterer ◽

Horst Dier ◽

Dagmar Nagel ◽

Tatjana Naebert ◽

Dietrich Althausen ◽

...

Keyword(s):

Evaluation Method ◽

Time Lag ◽

Correction Method ◽

Cirrus Clouds ◽

Temperature Dependent ◽

Upper Troposphere ◽

Statistical Comparison ◽

Daily Show ◽

Tropical Tropopause ◽

Humidity Profiles

Abstract Routine radiosonde relative humidity (RH) measurements are not reliable as they are presently used in the global upper-air network. The new Lindenberg measuring and evaluation method, which provides RH profile measurements with an accuracy of ±1% RΗ in the temperature range from 35° to −70°C near the tropical tropopause is described. This Standardized Frequencies (FN) method uses a thin-film capacitive polymer sensor of a modified RS90-H Humicap radiosonde. These research humidity reference radiosondes (FN sondes) are used to develop a correction method for operational RS80-A Humicap humidity profiles. All steps of correction and quality control for RS80-A radiosondes are shown: ground-check correction, time-lag and temperature-dependent correction, and the recognition of icing during the ascent. The results of a statistical comparison between FN sondes and RS80-A sondes are presented. Corrected humidity data of operational RS80-A sondes used in Lindenberg (4 times daily) show no bias when compared to FN radiosondes and have an uncertainty of about ±3% RH at the 1 σ or 68% confidence level from 1000 to about 150 hPa. Only a small dry bias of at most −2% RH remains in the lowest part of the boundary layer (up to 500-m height). Finally, some examples of corrected RS80-A RH profiles in cirrus clouds validated by lidar backscattering profiles in a region of the intertropical convergence (Maldive Islands) are demonstrated. The soundings indicate that ice-saturated and ice-supersaturated air above 10-km height were connected with cirrus clouds in all 47 investigated cases, and, second, that the corrected RS80-A RH profiles also provide good quality information on water vapor in the upper troposphere.

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Characteristics of tropical thin cirrus clouds deduced from joint CloudSat and CALIPSO observations

Journal of Geophysical Research Atmospheres ◽

10.1029/2008jd010675 ◽

2009 ◽

Vol 114 ◽

Cited By ~ 63

Author(s):

Taryn Haladay ◽

Graeme Stephens

Keyword(s):

Cirrus Clouds

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