The use of MODIS water vapro imagery, NWP model analysis, and pilot reports to diagnose turbulent mountain waves

A technique for forecasting turbulent mountain waves was investigated using MODIS and GOES-12 water vapor (6.7um) imagery combined with hourly analyses from the RUC model. The limited domain of the Colorado Rocky Mountain and Front range regions were chosen for the study. Upon examining MODIS water vapor imagery daily for 2004 within this domain, it was found that wave signatures related to orography were present approximately 25% of the time. To determine the probability of turbulence occurring in the waves seen in the imagery, pilot reports were examined for correlation. Approximately 90% of the severely turbulent days had wave signatures in the water vapor imagery during the time period of the reports. The wave signatures on the turbulent days had different appearances in the imagery than the signatures on the days that were less turbulent. The turbulent days had complex wave patterns with apparent interference and crossing wave fronts that extended downwind for a significant distance. The days that were less turbulent had wave signatures that were simpler with wave patterns that could be characterized as linear. The hourly RUC analyses showed that the atmosphere during the turbulent wave events had wind and temperature profiles appropriate for mountain waves. The RUC data combined with the MODIS water vapor imagery illustrates that, with high-resolution satellite imagery, it may be possible for turbulent situations due to mountain induced wave activity to be nowcasted and forecasted. Ultimately, an algorithm could be developed incorporating model output data and satellite imagery to automate mountain wave induced turbulence forecasting.