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B. B. Stankov, B. E. Martner, and M. K. Politovich

488 JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY VOLUME 12Moisture Profiling of the Cloudy Winter Atmosphere Using Combined Remote Sensors B. B. STANKOV AND B. E. MARTNERNOAA Environmental Technology Laboratory, Boulder, Colorado M. K. POLITOVICHResearch Applications Program, National Center for Atmospheric Research, Boulder, Colorado(Manuscript received 8 June 1994, in final form 30 September 1994)ABSTRACT A new method for

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Jacques Parent du Chatelet, Chiraz Boudjabi, Lucas Besson, and Olivier Caumont

Abstract

Refractivity measurements in the boundary layer by precipitation radar could be useful for convection prediction. Until now such measurements have only been performed by coherent radars, but European weather radars are mostly equipped with noncoherent magnetron transmitters for which the phase and frequency may vary. In this paper, the authors give an analytical expression of the refractivity measurement by a noncoherent drifting-frequency magnetron radar and validate it by comparing with in situ measurements. The main conclusion is that, provided the necessary corrections are applied, the measurement can be successfully performed with a noncoherent radar. The correction factor mainly depends on the local-oscillator frequency variation, which is known perfectly. A second-order error, proportional to the transmitted frequency variation, can be neglected as long as this change remains small.

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Paolo Di Girolamo, Donato Summa, and Rossella Ferretti

Abstract

The University of Basilicata Raman lidar system (BASIL) is operational in Potenza, Italy, and it is capable of performing high-resolution and accurate measurements of atmospheric temperature and water vapor based on the application of the rotational and vibrational Raman lidar techniques in the ultraviolet region. BASIL was recently involved in the 2005 International Lindenberg campaign for Assessment of Humidity and Cloud Profiling Systems and Its Impact on High-Resolution Modeling (LAUNCH 2005) experiment held from 12 September to 31 October 2005. A thorough description of the technical characteristics, measurement capabilities, and performances of BASIL is given in this paper. Measurements were continuously run between 1 and 3 October 2005, covering a dry stratospheric intrusion episode associated with a tropopause folding event. The measurements in this paper represent the first simultaneous Raman lidar measurements of atmospheric temperature, water vapor mixing ratio, and thus relative humidity reported for an extensive observation period (32 h).

The use of water vapor to trace intruded stratospheric air allows the clear identification of a dry structure (∼1 km thick) originating in the stratosphere and descending in the free troposphere down to ∼3 km. A similar feature is present in the temperature field, with lower temperature values detected within the dry-air tongue. Relative humidity measurements reveal values as small as 0.5%–1% within the intruded air. The stratospheric origin of the observed dry layer has been verified by the application of a Lagrangian trajectory model. The subsidence of the intruding heavy dry air may be responsible for the gravity wave activity observed beneath the dry layer.

Lidar measurements have been compared with the output of both the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5) and the European Centre for Medium-Range Weather Forecasts (ECMWF) global model. Comparisons in terms of water vapor reveal the capability of MM5 to reproduce the dynamical structures associated with the stratospheric intrusion episode and to simulate the deep penetration into the troposphere of the dry intruded layer. Moreover, lidar measurements of potential temperature are compared with MM5 output, whereas potential vorticities from both the ECMWF model and MM5 are compared with estimates obtained combining MM5 model vorticity and lidar measurements of potential temperature.

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Robert M. Rabin and Timothy J. Schmit

1. Introduction An outstanding problem in hydrometeorology is determining soil moisture content at high resolution over continental scales. Direct measurements of soil moisture are limited to specific sites and may be unrepresentative of larger areas. For this reason, there have been many efforts to develop remote sensing techniques to estimate surface moisture. Some success has been achieved in quantifying surface moisture where the vegetation cover is not too dense using passive microwave

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Larry M. McMillin and Murty G. Divakarla

of a satellite in which the temperature and moisture channels would have different scanning geometries. Rosenkranz et al. (1997) have discussed these and the effect of microwave scan angle on the accuracy of atmospheric temperature retrievals. Because of the possibility that there might be different scanning geometries for the two measurements, we consider the effects of scanning geometry on moisture retrievals and summarize the effect of scanning geometry on cloud contamination in the appendix

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Caroline M. Kiefer, Craig B. Clements, and Brian E. Potter

up to 860 m lower over fires than ambient conditions, which would require adding more than 4 g kg −1 of moisture to the plume. Other cases revealed a plume height up to 13 km where the ambient equilibrium level (EL) only reached 9.9 km, requiring an additional 3 g kg −1 and 3°C of moisture and temperature increase, respectively. The lower LCL and higher EL imply increased moisture in smoke plumes, which strengthen convective columns above fires. A study by Jenkins (2004) found that vertical

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William L. Smith, Wayne F. Feltz, Robert O. Knuteson, Henry E. Revercomb, Harold M. Woolf, and H. Ben Howell

moisture retrieval results were obtained from the radiance data collected, which compared favorably to radiosonde data used as ground truth ( Smith et al. 1990 ). Improvements in the system funded by the Department of Energy’s (DOE) Atmospheric Radiation Measurement (ARM) program produced an Atmospheric Emitted Radiance Interferometer (AERI) prototype system and finally the current operational version of the instrument ( Revercomb et al. 1993 ; Smith et al. 1993 ). AERI has evolved into a fully

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Joel A. Silver and David Christian Hovde

Fig. 1 . The major subsystems of the apparatus are the diode laser and its control electronics, the optical path, a pressure-controlled sample cell, controlled moisture flow generation, and the detectors and associated signal processing. For the WMS setup, the laser output is directly focused across the sample cell; the NC uses a fiber optic cable to transfer radiation to the cell and to the reference detector. a. Optical setup While laser modules incorporating an optical isolator, thermoelectric

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Paul E. Ciesielski, Hungjui Yu, Richard H. Johnson, Kunio Yoneyama, Masaki Katsumata, Charles N. Long, Junhong Wang, Scot M. Loehrer, Kathryn Young, Steven F. Williams, William Brown, John Braun, and Teresa Van Hove

over the Maritime Continent and western Pacific warm pool region. A primary component of this enhanced network were six core sounding sites in central IO that formed two quadrilateral sounding arrays, one north and one south of the equator. These two arrays will provide the observations necessary for diagnostic studies of heat and moisture budgets from which the properties of convection can be inferred ( Yanai et al. 1973 ). In addition, the data allow for the computation of advective properties of

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Timothy J. Schmit, Jun Li, Steven A. Ackerman, and James J. Gurka

continue the current GOES sounder products (legacy temperature and moisture profiles, total precipitable water, layer precipitable water, and instability indices). Information content analysis was also conducted to demonstrate that both the current GOES sounder and ABI have limited vertical information and accuracy for atmospheric profiling when compared with advanced IR sounders. This paper outlines the potential applications of high-spectral-resolution IR observations that have led many research and

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