GNSS Precipitable Water Vapor from an Amazonian Rain Forest Flux Tower

• DOI: 10.1175/jtech-d-11-00082.1
• Publication Date: 2011-08-05T17:22:58Z
• Authors: David K. Adams; Rui M. S. Fernandes; Jair M. F. Maia
• Keywords: Signals; Rainforest; Processing Technique; Gnss; Precipitation Intensity; Satellites; Rain; Convective System; Gps; Convective Storms; 0207 environmental engineering; 02 engineering and technology; Processing Method; Processing; Precipitation Assessment; 01 natural sciences; Meso Scale; Mesoscale Process; Rain Forests; Amazonia; Global Positioning System; Mesoscale Networks; Vertical Distributions; Complex Interaction; Nonideal; Temporal Variation; Instrumentation/sensors; 0105 earth and related environmental sciences; Mesoscale Meteorology; Geodetic Satellites; Natural Convection; Navigation Systems; Sensors; Accuracy Assessment; Navigational Satellites; Gnss Receivers; Forestry; Deep Convection; Positioning System; Signal Receivers; Water Vapor; Precipitable Water Vapor; Oscillating Platform; Spatial Resolution; 13. Climate action; Water Vapor Fields; Amazon Rainforest; Geodesy

Abstract Understanding the complex interactions between water vapor fields and deep convection on the mesoscale requires observational networks with high spatial (kilometers) and temporal (minutes) resolution. In the equatorial tropics, where deep convection dominates the vertical distribution of the most important greenhouse substance—water—these mesoscale networks are nonexistent. Global Navigational Satellite System (GNSS) meteorological networks offer high temporal/spatial resolution precipitable water vapor, but infrastructure exigencies are great. The authors report here on very accurate precipitable water vapor (PWV) values calculated from a GNSS receiver installed on a highly nonideal Amazon rain forest flux tower. Further experiments with a mechanically oscillating platform demonstrate that errors and biases of approximately 1 mm (2%–3% of PWV) can be expected when compared with a stable reference GNSS receiver for two different geodetic grade receivers/antennas and processing methods [GPS-Inferred Positioning System (GIPSY) and GAMIT]. The implication is that stable fixed antennas are unnecessary for accurate calculation of precipitable water vapor regardless of processing techniques or geodetic grade receiver.