RGB Airmass and Dust products NASA SPoRT CIRA

RGB Air Mass RED (6.2 – 7.3) –vertical moisture distribution GREEN ( ) – tropopause height based on ozone concentration BLUE (6.2) – upper level moisture Tropical air masses are green to tan colors while polar air masses are purple. Jet streaks appear bright red due to stratospheric intrusions they cause. Primary Applications: – Identify boundary of polar and tropical air masses – Locate areas of large potential vorticity due to jet streaks Warm, moist upper levels Warm, moist mid levels Cool, moist upper levels Cold, dry upper levels Cool, moist upper levels Pot. Vorticity, Jet Streak

RGB Air Mass Details Color Band / Band Diff. Physically Relates to…. Little contribution to composite indicates….. Large contribution to composite indicates ….. Red6.7 – 7.3 Vertical water vapor difference Moist conditions high levels Dry conditions at high levels Green Estimate of tropopause height based on ozone. Polar (tropical) air has higher (lower) ozone concentrations Tropopause height is low. Typically indicates a polar air mass, where 9.7 has very cold brightness temperature compared to 10.7 Tropopause height is high. Likely a tropical air mass where the two channels will have similar brightness temperature values Blue6.7 (inverted, meaning warm to cold scale ) Water Vapor in layer from ~200 – 500 mb Dry at upper levels Warm brightness temperatures have little blue Moist at upper levels Cold brightness temperatures result in lots of blue Above are details from SPoRT’s RGB Quick Guide to help understand color contributions to resulting composite. It can be found at: %20Mass%20Reference%20Guide.pdf EUMETSAT has developed color interpretation guides for RGBs. See:

Hurricane Philippe (2011) RGB Air Mass Applications for extratropical transition monitoring Stratospheric intrusion and associated jet streak shown in red coloring Helps to indicate when transition is beginning to occur Blue indicating cooler air resulting from more baroclinic activity to the southwest (i.e. there’s less green here so less tropical in nature)

Hurricane Philippe (2011) RGB Air Mass Training Module RGB, GFS 500mb Height and Vorticity 00Z on 10/8 RGB is better than WV to compare to model forecasts/analysis of

Dust Event from 07/20/12 RGB Dust Product RED (12 – 10.8) –Optical Thickness GREEN (10.8 – 8.7) – Particle Phase BLUE (10.8) – Object surface temperature Dust areas are in magenta shades. Over water, magenta dust is influenced by thermal signature of SST. Over land, intense magenta from storm outflows show dust initiation transport. Primary Applications: – Identify airborne dust (magenta coloring) from cloud features – Highlights moisture boundaries Note more blue vs magenta shades in areas where tropical storms are located. Dust Lack of Dust

RGB Dust Details Color Band / Band Diff. Physically Relates to…. Little contribution to composite indicates….. Large contribution to composite indicates ….. Red12.0 – 10.8 Optical thickness Thin clouds. Difference is negative. Less of the 12um channel passes through the clouds (colder brightness temperature) than the 10.8um channel Thick clouds or dust. Difference is positive. More of the 12um channel passes through the clouds (Warmer brightness temperature) than the 10.8um channel Green10.8 – 8.7 Particle phase (ice vs water) or com Ice particles or particles of similar characteristics have small difference High clouds over desert regions – emission from surface overwhelms the relationship Blue10.8 Temperature of surfaceCold surfaceWarm surface Color Physical Meaning RedGreenBlue Dust at 400mb at night Dust at 700mb at night Dust at 900mb at night Dust (Day time) Above are details from SPoRT’s RGB Quick Guide to help understand color contributions to resulting composite. It can be found at: GB%20Dust%20Reference%20Guide.pdf EUMETSAT has developed color interpretation guides for RGBs. See: tion.html tion.html