First, some house keeping. I’ve been remiss is posting articles for discussion here, in spite of my promises to do just that. My apologies. Most of you know I’ve been pondering our sea level and the assumption of our continuous sea level rise. See here. For the most part, the conversation has been confined to satellite data. And, more information has come to light. While I was playing the role as a contrarian at WUWT, (sometimes, its fun to be skeptical of assumptions made by supposed skeptics) 🙂 Dave Wendt, a frequent commentator at WUWT, addressed my skepticism over the sea level. See here. Here is part of his offering,…
“I’ve tried to get this point across in a quite a number of comments here over the last couple of years, without a great deal of success it would seem, given the large number of comment threads devoted to arguing vociferously about whether GMSL is changing by 1.9mm, 2.6mm, 3.1mm. or some other statistician’s fantasy number. I’ve tried recommending that people review this document.
It’s the Data Products Handbook for the JASON2 satellites that provide the observations from which the sea level data are derived….. I particularly like this bit from the section on the inverse barometric correction 5.10.1
“The uncertainty of the ECMWF atmospheric pressure products is somewhat dependent on location. Typical errors vary from 1 mbar in the northern Atlantic Ocean to a few mbars in the southern Pacific Ocean. A 1-mbar error in pressure translates into a 10 mm error in the computation of the IB effect.”
So, that’s another paper to read on how our satellites can’t really tell us squat. Sigh. I should probably spend much more time reading and understanding all of that, but Latitude, being the fountain of information that he is, has already brought to my attention pretty much the same thing, except it is for Envisat instead of Jason2. UHHGGHH!!!! Well, all of that’s going to have to wait for another day or someone one else to give me a guest post or some such!
After reading some of the Envisat documentation, it occurred to me that most of the documentation regarding satellite data was confirmed because it gave them back information that generally agreed with the physical readings of the tidal gauges. Never mind that the equipment was supposed to be, at least in part, calibrated to the gauges, (the other part models!!!). It occurred to me, that it should be pretty simple to confirm this assertion. By that I mean that the physical readings confirm general sea level rise. Steve Goddard, has in the past, presented many tidal gauge readings,…… mostly making fun of people worried about sea level rise when in their particular locality of interest, the sea level wasn’t rising….. I particularly like those posts. So, I asked him what the best source was….. he directed me to http://www.psmsl.org/ , THE PERMANENT SERVICE FOR MEAN SEA LEVEL. So, off I go on a quick and easy adventure. After perusing some of the downloaded data, it occurred to me that I’d have to set up some criteria about how I’m going to go about determining sea-level by the physical readings. PSMSL said they had over 2000 records……. well, if they do, they’re hiding a lot of it, I can find only 1270 records. To start, I downloaded the yearly data. I figured the easiest way to start was to get the easiest stuff and drill down if I feel compelled.
For this exercise, I’m just doing a quick and easy determination. PSMSL does play with the data, and the final product is “rlr” data, as opposed to the more raw “metric”. For now, I’m not making any judgment about their data manipulation, and I’m assuming it was correct. I decided I only wanted data for the last 30 years……. I’m not interested in the sea level of 1870 or any other years except the most recent. I also decided that if the record was missing more than 1year in the last 30, I’d throw it out. For the ones that had only one missing, I’d infill the value with the average between the year prior and after. Further, I wanted the most recent data so the data gets thrown out unless it holds the yearly average for 2010. Simple enough, right? As I stated, there are only 1270 records. After throwing out the records that don’t fit my criteria, I’m up to record number 134!(There are several record numbers missing.) I’m over 10% done! I have 13 whole records for my simple exercise. 😐 Why would I have expected anything different? I should probably stop here. Right now I’m on pace to get 1-2% of the records from the PSMSL database to fit my criteria. I’ll persevere and finish. If I do end up with a usable sampling, I’ve another problem to deal with that probably needs answered before I finish. Distribution. If one goes to the link, we see that Japan and the U.S. coasts are over represented if we’re going to come up with a global average. Now, I don’t know how the U.S. and Japanese stations will stand up to my criteria, but I suspect they’ll have the best and most recent continuity. How would I deal with this? There are several different approaches, but I’m not sure which is the best. Any suggestions?
The lack of continuity and recent readings are disquieting to say the least. But perhaps the situation will improve as I move through the data. The missing stations are a bit disquieting, too. I haven’t read all of the documentation at PSMSL, but I haven’t come across an explanation for the missing 800 stations. GISS type of elimination? Surely that’s not the case, but ………
Any thoughts, critiques, questions or concerns would be warmly received.