Satellite Data

We've passed the 50th anniversary of the first meteorological satellite*, on to 60! Even though satellites have been used for decades, it's still far from simple to do so. Or, rather, it is much more involved than I used to think. I suppose it shouldn't really have been a surprise. Automated weather stations on earth have plenty of problems, and they're operating at earthly temperatures, near somebody who can fix minor problems if they occur, and do so before they become major problems.

By way of my day job (again, I do _not_ speak for my employer), I use satellite data and do so heavily enough that I'm on the mailing list for operational updates about the current status of the satellites, data receiving stations, and other parts of the system between my desk (well, the supercomputer at work) and the satellite.

One thing which has really impressed itself on me is that there is far more to satellites than launching them and waiting for lovely data to flow forth. Second is that there must be a large number of very highly skilled people working between the satellite and my desk to ensure that the data flows reliably, at high quality, and in a timely fashion.

Fortunately, though I'm about to name some challenges and problems, they're _known_ problems and challenges, with solutions. Engineers don't like leaving problems standing. Problems are things to be solved! So, a few stories:

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March for science

Dates to be determined, but there is an effort developing to have a march for science in the US.  There's a facebook group, and facebook messenger at @marchforscience, twitter as @ScienceMarchDC, and the main web site.  Things are evolving rapidly, having started very recently and now being over 90,000 in the facebook group.  One change being that it has moved from being a march by scientists to being a march for science.

Something which occurs to me as useful to know is senators and representatives whose states or districts have large numbers of scientists or companies which do large amounts of science or contracting.  Some which occur to me:

Some Large Centers

(Places, Senators, Congressperson)

NASA Goddard Space Flight Center, Greenbelt, MD -- Chris van Hollen, Ben Cardin --  Steny Hoyer (MD-5)
NOAA Headquarters, Silver Spring, MD -- Chris van Hollen, Ben Cardin -- ?Jeremy Raskin
Argonne National Lab, IL --
NASA Marshall, Huntsville, AL --
NASA Ames, CA --
NASA Johnson, Houston, TX --
Los Alamos National Lab, Los Alamos, NM --
National Hurricane Center, Miami, FL --
National Severe Storms Laboratory, Norman, OK --
National Climatic Data Center, Asheville, NC --
Center for Disease Control, Atlanta, GA --

Companies that build earth satellites:
Boeing (HQ in Seattle, WA, but many other offices) --
Lockheed Martin (HQ in Bethesda, MD, ditto) -- Chris van Hollen, Ben Cardin --
Orbital ATK (HQ Dulles, VA, ditto) --
Space Systems Loral (HQ Palo Alto, CA, ditto)

Biomed/Biotech/Pharmaceuticals
Computers/Technology
...

I've missed many areas, please add to my list.  Also, please work on adding to the list of states and congressional districts.  I expect that every state and most congressional districts have at least one large employer which depends on science.  It helps to have names and places.

Recent Reading

If you hadn't noticed last time I wrote about my reading, I enjoy reading old books, and books about old things.  One of the interesting, to me, things about math/science/engineering is that it is incremental.  Each generation builds on what the preceding generations learned or accomplished.  Related truth is that I can read some of the best work from all people, across all of time.  Books are my time machine.

Richard J. Gillings, Mathematics in the Time of the Pharoahs, Dover Books. 

Ed. T. L. Heath, The Works of Archimedes, Dover Books.

Tacitus, The Agricola and the Germania, Penguin Classics.

Craig Martin, Renaissance Meteorology: Pomponazzi to Descartes, Johns Hopkins University Press.

A. S. Kompaneyets, Theoretical Physics, Dover Books.

Michael W. Shaw, Kids and Teachers, Tardigrade Science Project Book, Fresh Squeezed Publishing.

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2016 Tough on Sea Ice Satellites

The last several weeks have been hard on the satellites people like me use most for determining sea ice coverage.  We use passive microwave instruments on a number of different satellites.  The 'passive' in its name means that it doesn't emit microwaves.  It just sits back and collects the emissions from where it's looking.  In this, the instrument is rather like our eyes.

Different centers use different instruments and different combinations of instruments.  The main ones are:
SSMI on DMSP F-15, launched on 12 December 1999 (pushing 17 years!)
SSMI-S on DMSP F-16, launched 18 October 2003 (pushing 13!)
SSMI-S on DMSP F-17, 4 November 2006 (almost 10!)
SSMI-S on DMSP F-18, 18 October 2009 (approaching 7)
SSMI-S on DMSP F-19, 3 April 2014 (only 2)
AMSR2 on GCOM-W, 18 May 2012 (nearly 4)

A word about the names.  SSMI is Special Sensor Microwave Imager.  'Imager' is the key word.  With satellites, 'imager' means that the instrument is designed to be able to see (mostly) the surface.  Handy for us sea ice people.  DMSP is the Defense Meteorological Satellite Program -- the US Department of Defense operates these satellites.  SSMI-S (or SSMI-SU) is the SSMI -- Sounder (or Sounding Unit).  Means that in addition to the regular SSMI observing of the surface, it also carries some sensors that can do 'sounding'.  Sounding is to see what's going on in the atmosphere rather than mostly the surface.  (Name comes from the weather balloons -- which collect data known as soundings.)  AMSR is Advanced Microwave Sounding Radiometer.  It's operated by the Japanese Space Agency (JAXA).  The advance is that it is able to see more detail and the much older designs in the SSMI and SSMI-S. 

So, to our stories of woe.  All of these instruments are designed for 5 years' operation.  F-15 giving (mostly) good data after 17 years is spectacular for this type of satellite.  Notice that most of these potential data sources are already past their design life.  Since February 2016:

F-16: the sounding channels quit working early February
F-17: April 5th data quality impaired on one of the surface imaging channels, data volumes sent are greatly reduced.
F-18: Mostly ok, but reduced volume of data.  Many orbits' data not making it through.
F-19: Data ceased flowing February 2
AMSR2: Data outage afternoon of April 15th through morning of April 16th.

F-15, the oldest of the crowd, is still sending basically normal data volumes at basically normal volumes.

So, hiccups all around the sea ice analysis world.  The NSIDC was using only the F-17 SSMI-S, so has to rebuild their system to work with another instrument.  The AMSR2 temporary outage affected some centers seriously as they relied only on that instrument.  The US NWS uses both F-15 and F-17, and so far seems to be ok.  I haven't checked the operating status of the OSI-SAF sea ice (European analysis).  If I remember correctly, they also use more than one instrument, so should also be ok.

More gory details below the fold ...

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Autism Awareness Month, 2016

A heads up that it's autism awareness month again.  Autism hasn't changed much in the past year, so I don't have much new to say.  My 2015 post covers what I have to say myself.  In brief: people are people, including autistic people.  People are all similar, because we're people.  And people are all different, because we are people.  All of this applies to autistic people too, no more, no less.