CAMEX-4 DC-8 Nevzorov Total Condensed Water Content Sensor

Table of Contents

Introduction

The Nevzorov total condensed water content sensor flew on the NASA DC-8 during the CAMEX-4 experiment. It is an instrument that measures the total condensed water content of the sample of air which passes through it. The Nevzorov probe is a condensed water content of the sample of air which passes through it. The Nevzorov probe is a constant temperature hot wire probe and consists of two separate sensors for measuring the total water content (liquid water [which includes frozen species] content, LWC,and total water content, TWC) of clouds and fog in the range between 0.003 gm-3 and 3 gm-3. Both sensors are mounted on a common sensor head, providing alignment parallel to the airflow. Within an airspeed envelope between 10 m/s and 180 m/s, the errors of the probe are within 10%.

The principle of operation is based on the determination of the heat loss of the sensors by evaporation of cloud water and by convective heat losses. Each sensor consists of a collector and a reference winding. The reference winding is shielded from impacts of cloud particles and therefore allows the direct calculation of the convective heat loss. The LWC and TWC sensors consist of close single-layer windings of enamel-covered nickel wires. For the TWC sensor, the collector winding is cemented to the hollow cone of a textolite cylinder while the reference sensor is wound within a shallow groove cut into the same cylinder. For the LWC sensor, both windings are wound on solid copper rods and cemented to opposite edges of a flat textolite plate. Because of this design, the LWC collector sensor is only responding to water drops since ice crystals are reflected. Due to its conical shape, the TWC collector sensor responds to water drops and ice crystals. Both sensors are operated separately by control boxes inside the fuselage, maintaining a fixed temperature for the collector windings and determining the power that is necessary to keep the temperature constant at the defined level.

Each mission (no more than one per day) for which there were data collected has a file of the form:

c4dnevzor_2001.267_010418.txt

where c4dnevzor represents a CAMEX-4 dataset for the Nevzorov probe, 2001.267 is the yyyy.ddd and 010418 is the mission number.

Data Format

The data files are in ascii format, and are self explanatory. A sample is shown below:

Project: CAMEX-4
Instrument: Nevzorov Total Condensed Water Content Sensor
Flight Date (mmddyyyy): 09062001
Start Time (hhmmss UTC): 163900
Stop Time (hhmmss UTC): 194000
Date processed: Tue May 21 16:37:22 2002

Ordering Data

To order these data or for further information, please contact:

Global Hydrology Resource Center
User Services
320 Sparkman Drive
Huntsville, AL 35805
Phone: 256-961-7932
E-mail: support-ghrc@earthdata.nasa.gov
Web: http://ghrc.nsstc.nasa.gov/