|
|
Post by johnm on May 16, 2017 10:33:19 GMT
On the 16th May 2017 the spaceweather.com website published a statement from Cora Randall, a member of the AIM science team at the University of Colorado, ' "Currently, we are not retrieving cloud data. The orbit of the spacecraft has precessed, and we are transitioning to a new way of pointing. We need a bit more time to settle the spacecraft pointing and hope to be back online by the end of May." '. Also the plot of mesopause humidity and temperature which shows when NLC are possible over the UK at www.geos.ed.ac.uk/~hcp/meso_ts/ is broken not having updated since September 2016. I have emailed the owner of this page to ask if it can be fixed but have not yet had a response. It looks as though we may have to rely on the Mark One eyeball for sightings this year. I have updated my Excel Spreadsheet that calculates the times that NLC are most likley to be seen for a specified location. This can be downloaded from the NLC Observing page on my website at www.JohnMurrell.org.uk. Any questions to me either via the link on my website or via this board. You will need to enable the macros in the spreeadsheet to calculate the times for different locations. The results for the currrent date are now highlighted in yellow to make them easier to see. Good luck with your 2017 observations John Murrell |
|
|
|
Post by johnm on May 18, 2017 21:01:05 GMT
The plot of mesopause humidity and temperature which shows when NLC are possible over the UK at www.geos.ed.ac.uk/~hcp/meso_ts/ has now been fixed - Thanks to Hugh Pumphrey of The University of Edinburgh who maintains that page for fixing it. The temperatures and humidity levels seem to be heading the right way for NLC to form. Additional Information 19/5/2017 One thing that should be noted is that the Mesopause plot on the link above shows the conditions above the UK. Measurements for other areas requires seperate analysis of the MLS data. I am not sure how much spacial variation there is so how large an area the measurements are applicable to. |
|
|
|
Post by adrien on May 29, 2017 8:35:31 GMT
I have received confirmation by scientists at the British astronomical association and the Laboratory for Atmospheric and Space Physics at the University of Colorado that the CIPS images of NASA's AIM satellite will not be available for at least another two weeks as they are working on updating the software to make up for the Earth's orbit, making ground observations even more important. I have reported my first NLC observation of the season on May 25-26th 2017 in Denmark, in here and to them, and I am keeping an on any other reports! Many thanks to the community for the precious reports!
|
|
|
|
Post by johnm on Jun 4, 2017 9:48:11 GMT
Adrien, I had a look at your movie of suspect NLC clouds from 25/26 May 2017 that I found on the internet. To me they look like Cirrus as they are moving to the west and almost all NLC seem to move towards the East. Also could not see any evidence of gravity waves in the clouds which are commonly visible in the movies. 25/26th May would be very early for the first sightings - people quote around 11th June (missummer -10) as the normal formation date of the first NLC. Of course we don't have any AIM images to help with confirmation. The video by Jacek Stegman on YouTube at www.youtube.com/watch?v=IGQ6mJqwwks is a good example. This shows both the Eastward motion and also the gravity waves causing stationary structures that result is something that looks a bit like a waterfall. Unfortunatly the rest of his time lapse videos are not on line. Regards John |
|
|
|
Post by adrien on Jun 12, 2017 10:17:11 GMT
Adrien, I had a look at your movie of suspect NLC clouds from 25/26 May 2017 that I found on the internet. To me they look like Cirrus as they are moving to the west and almost all NLC seem to move towards the East. Also could not see any evidence of gravity waves in the clouds which are commonly visible in the movies. 25/26th May would be very early for the first sightings - people quote around 11th June (missummer -10) as the normal formation date of the first NLC. Of course we don't have any AIM images to help with confirmation. The video by Jacek Stegman on YouTube at www.youtube.com/watch?v=IGQ6mJqwwks is a good example. This shows both the Eastward motion and also the gravity waves causing stationary structures that result is something that looks a bit like a waterfall. Unfortunatly the rest of his time lapse videos are not on line. Regards John Hi John, do you mean this video? www.youtube.com/watch?v=8zsYVhqqV2s . Cirrus clouds would not shine like this at night, especially so close to the horizon. Plus you can definitely recognize type II a and b NLC'c. The theory that NLC move toward the east is right, as you can see on several of my time lapses, they move more towards the east and south, but sometimes they also seem to move towards the west (ex: www.youtube.com/watch?v=Ka2h8Xk7dUw or www.youtube.com/watch?v=2acs3ZuUg1Y&t=35s). Their behavior is really not that well understood and I am going on an airborne mission with the NASA-funded project PoSSUM this summer to investigate it up close. Regarding the dates, May 25-26th are actually average starting dates for nucleation of NLC's and scientists at the British astronomical society, laboratory for atmospheric and space physics in Boulder, CO, but also on the NLC network have reported positive published sightings starting no later than May 19-20 as first dates! If you meant this video instead from the 21.05.17 www.youtube.com/watch?v=prEPqlo_mDQ then I totally agree with you, even though it was confirmed by scientists, I'm still not convinced they are NLC, mostly because of their brightness and the fact that they move at the same speed and direction as the tropospheric clouds  Thanks for your input! Regards Adrien |
|
