Exploring the effects of GOES-17 parallax over Alaska
![GOES-17 “Red” Visible (0.64 µm) and](https://cimss.ssec.wisc.edu/satellite-blog/images/2020/06/ak_vis-20200627_210032.png)
Topography, GOES-17 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]
A plot of rawinsonde data from Nome (below) showed the strong southwesterly winds that existed within most the troposphere on that day. The tropopause temperatures were around -51ºC at altitudes of 9.4-9.6 km — indicating that these high-altitude rotor clouds were forced by vertically-propagating waves initiated by interaction of the anomalously-strong southerly/southwesterly lower-tropospheric flow with the west-to-east oriented mountain ranges.
Comparisons of topography and Visible/Infrared images from Suomi NPP and GOES-17 around 1320 UTC and 2140 UTC are shown below. Since there is generally very little parallax offset associated with imagery from polar-orbiting satellites (such as Suomi NPP), the rotor cloud appeared closer to the topography that helped to force development of that cloud feature.![Topography, Suomi NPP VIIRS Visible (0.64 µm) and GOES-17 "Red" Visible (0.64 µm) images around 1320 UTC [click to enlarge]](https://cimss.ssec.wisc.edu/satellite-blog/images/2020/06/200627_1320utc_topo_suomiNPP_goes17_visible_AK_anim.gif)
Topography, Suomi NPP VIIRS Visible (0.64 µm) and GOES-17 “Red” Visible (0.64 µm) images around 1320 UTC [click to enlarge]
![Topography, Suomi NPP VIIRS Infrared Window (11.45 µm) and GOES-17 "Clean" Infrared Window (10.35 µm) images around 1320 UTC [click to enlarge]](https://cimss.ssec.wisc.edu/satellite-blog/images/2020/06/200627_1320utc_topo_suomiNPP_goes17_infrared_AK_anim.gif)
Topography, Suomi NPP VIIRS Infrared Window (11.45 µm) and GOES-17 “Clean” Infrared Window (10.35 µm) images around 1320 UTC [click to enlarge]
![Topography, Suomi NPP VIIRS Visible (0.64 µm) and GOES-17 "Red" Visible (0.64 µm) images around 2140 UTC [click to enlarge]](https://cimss.ssec.wisc.edu/satellite-blog/images/2020/06/200627_2140utc_topo_suomiNPP_goes17_visible_AK_anim.gif)
Topography, Suomi NPP VIIRS Visible (0.64 µm) and GOES-17 “Red” Visible (0.64 µm) images around 2140 UTC [click to enlarge]
![Topography, Suomi NPP VIIRS Infrared Window (11.45 µm) and GOES-17 "Clean" Infrared Window (10.35 µm) images around 2140 UTC [click to enlarge]](https://cimss.ssec.wisc.edu/satellite-blog/images/2020/06/200627_2140utc_topo_suomiNPP_goes17_infrared_AK_anim.gif)
Topography, Suomi NPP VIIRS Infrared Window (11.45 µm) and GOES-17 “Clean” Infrared Window (10.35 µm) images around 2140 UTC [click to enlarge]