9.2.3 Performance Characteristics of Remote Sensing Systems
Many
of the studies that have been performed to estimate the accuracy and
precision of remote sensors were based on
inter-comparisons to tower-based measurements. These comparisons
have generally assumed that the tower measurements provide the known
standard and are representative of the
same environment measured by the remote sensors. However, differences
between point measurements from in situ sensors located on the tower
and volume-averaged measurements from the
remote sensors located near the tower are expected to lead to differences
in the results, even though conditions for these inter-comparisons are
likely as close to “ideal” as one
could expect. The performance of remote profiling instrumentation is greatly influenced by individual site characteristics,
instrument condition, and operating parameters established
for the equipment.
Table
9-1 includes estimates of expected performance characteristics for remote
sensing systems that are installed and working properly. These results
should be used for establishing data
quality objectives for upper-air programs and as a basis for interpreting
results from inter-comparison programs or
performance audits of upper-air equipment (see Section 9.6). To avoid ambiguities in wind direction associated with
light and variable winds, it is recommended that the
wind direction comparability calculations be made only when actual wind
speeds are greater than approximately 2
ms -1 .
9. UPPER-AIR MONITORING
9.1 Fundamentals
9.1.1 Upper-Air Meteorological Variables
9.1.2 Radiosonde Sounding System
9.1.3 Doppler Sodar
9.1.4 Radar Wind Profiler
9.1.5 RASS
9.2 Performance Characteristics
9.2.1 Definition of Performance Specifications
9.2.2 Performance Characteristics of Radiosonde Sounding Systems
9.2.3 Performance Characteristics of Remote Sensing Systems
9.3 Monitoring Objectives and Goals
9.3.1 Data Quality Objectives
9.4 Siting and Exposure
9.5 Installation and Acceptance Testing
9.6 Quality Assurance and Quality Control
9.6.1 Calibration Methods
9.6.2 System and Performance Audits
9.6.3 Standard Operating Procedures
9.6.4 Operational Checks and Preventive Maintenance
9.6.5 Corrective Action and Reporting
9.6.6 Common Problems Encountered in Upper-Air Data Collection
9.7 Data Processing and Management (DP&M)
9.7.1 Overview of Data Products
9.7.2 Steps in DP&M
9.7.3 Data Archiving
9.8 Recommendations for Upper-Air Data Collection