Wednesday, May 2, 2012

3735.txt

date: Tue Nov 10 12:40:26 2009
from: Phil Jones <p.jonesatXYZxyz.ac.uk>
subject: Re: Twentieth Century Reanalysis preliminary version 2 data - One
to: Gil Compo <compoatXYZxyzorado.edu>

Gil,
One other good plot to do is this. Plot land minus ocean. as a time series.
This should stay relatively close until the 1970s. Then the land should start moving away
from the ocean.
This departure is part of AGW. The rest is in your Co2 increases.
Cheers
Phil
Gil,
These will do for my purpose. I won't pass them on. I am looking forward to the draft
paper. As you're fully aware you're going to have to go some ways to figuring out what's
causing the differences.
You will have to go down the sub-sampling, but I don't think it is going to make much
difference. The agreement between CRU and GISS is amazing good, as already know. You ought
to include the NCDC dataset as well.
[1]http://www.ncdc.noaa.gov/oa/climate/research/anomalies/index.html the ERSST3b dataset.
In the lower two plots there appear to be two types of differences, clearer in the
NH20-70 land domain.
The first is when reanl20v2 differs for a single year (like a year in the last 1960s, 1967
or 1968) and then when it differs for about 10 years or so. It is good that it keeps coming
back. For individual years there are a couple of years in the first decade of the 20th
century (the 1900s).
The longer periods are those you've noticed - the 1920s and the 1890s. There is also
something up with the period 1955-65 and the 1970s. The 1920s seems to get back then go off
again from about 1935 to early 1940s. Best thing to try and isolate some of the reasons
would be maps for decades or individual years. For the 1920s I'd expect the differences to
be coming from Siberia as opposed to Canada. I think the 1890s might be just down to
sparser coverage. The 1890s is the only period where the difference brings your pink line
back towards the long-term zero. All the others have the pink line more extreme than the
HadCRUT3/GISS average.
Rob Allan just called. I briefly mentioned this to him. He suggested maps of data input
during these times. He also suggested looking at the spread of the ensembles. Your grey
spread is sort of this, but this is a different sort of ensemble to what Rob implied you
might have?
One final thing - don't worry too much about the 1940-60 period, as I think we'll be
changing the SSTs there for 1945-60 and with more digitized data for 1940-45. There is also
a tendency for the last 10 years (1996-2005) to drift slightly low - all 3 lines. This may
be down to SST issues.
Once again thanks for these! Hoping you'll send me a Christmas Present of the draft!
Cheers
Phil
At 20:45 09/11/2009, you wrote:

Phil,
1. I didn't get the attached.
Both version1 and version2 use HadISST1.1 for SST and sea ice.
2. time-varying CO2, volcanic aerosols, and solar variability (11-year cycle until 1949,
"observed" after that) are specified.
Attached is a research figure. Please do not share.
In it, I have plotted the annual average (top panel) 50S to 70N global average 2m
temperature from 20CRv2, SST/2m temperature from HadCRU3, SST/2m temperature from
GISTEMP 1200km, and the 90% range of 2m air temperature from 25 CMIP3 models that can be
extended beyond their 20C3M runs with SRESA1B. The ensemble mean is the thick gray
curve. Averages are July-June.
(middle panel) 50S to 70N land-only 2m temperature from 20CRv2, 2m temperature from
CRUTEM3, 2m temperature from GISTEMP land-only 1200km. CMIP3 data is the same.
(bottom panel) same as middle panel but for Northern Hemisphere land-only (20N to 70N).
Anomalies are with respect to 1901-2000. period is July 1891 to June 2005. The CRU
(HadCRU) curves are supposed to be black.
No data has been masked by another dataset's observational availability, but missing
values are not included in that dataset's area-weighted average.
Your ERA-Interim finding about it being warmer seems to be the case in the late 19th
century but not the early 1920's.
Note that the only thermometer data in the magenta curve (20CRv2) is the HadISST1.1 over
oceans. The two landonly panels are independent of thermometers, aside from the
specified SSTs.
There are some very interesting differences, particulary late-19th century, 1920s, and
WWII.
Correlations (I told you this was research, right?). The second pair is for linearly
detrended data.
GLOBE (70N-50S)

reanl20v2.70n50s.landocean.juljun
hadcru3.70n50s.landocean.juljun 0.94370

reanl20v2.70n50s.landocean.juljun
hadcru3.70n50s.landocean.juljun 0.82017

reanl20v2.70n50s.landocean.juljun
gistemp_combined1200.70n50s.landocean.juljun 0.95284

reanl20v2.70n50s.landocean.juljun
gistemp_combined1200.70n50s.landocean.juljun 0.85808

hadcru3.70n50s.landocean.juljun
gistemp_combined1200.70n50s.landocean.juljun 0.99088

hadcru3.70n50s.landocean.juljun
gistemp_combined1200.70n50s.landocean.juljun 0.97383
GLOBAL LAND (70N-50S)

reanl20v2.70n50s.landonly.juljun
cru3.70n50s.landonly.juljun 0.85167

reanl20v2.70n50s.landonly.juljun
cru3.70n50s.landonly.juljun 0.68755

reanl20v2.70n50s.landonly.juljun
gistemp_land1200.70n50s.landonly.juljun 0.81469

reanl20v2.70n50s.landonly.juljun
gistemp_land1200.70n50s.landonly.juljun 0.60152

cru3.70n50s.landonly.juljun
gistemp_land1200.70n50s.landonly.juljun 0.98050

cru3.70n50s.landonly.juljun
gistemp_land1200.70n50s.landonly.juljun 0.95316
NH Land (20N-70N)

reanl20v2.nh_nohigh.landonly.juljun
cru3.nh_nohigh.landonly.juljun 0.82956

reanl20v2.nh_nohigh.landonly.juljun
cru3.nh_nohigh.landonly.juljun 0.67989

reanl20v2.nh_nohigh.landonly.juljun
gistemp_land1200.nh_nohigh.landonly.juljun 0.79247

reanl20v2.nh_nohigh.landonly.juljun
gistemp_land1200.nh_nohigh.landonly.juljun 0.59900

cru3.nh_nohigh.landonly.juljun
gistemp_land1200.nh_nohigh.landonly.juljun 0.98001

cru3.nh_nohigh.landonly.juljun
gistemp_land1200.nh_nohigh.landonly.juljun 0.95880
I thought that correlations of 0.8 to 0.85 were high for an independent dataset this
long. I think that these are higher than the proxies?
The global isn't that fair because we have the HadISST.
The correlations are about the same as for AMIP runs, though. See
Hoerling M., A. Kumar, J. Eischeid, B. Jha (2008), What is causing the variability in
global mean land temperature?, Geophys. Res. Lett., 35, L23712,
doi:10.1029/2008GL035984.
It will be interesting to see if the masked numbers change.
Let me know if you need anything else on this for your essay material.
best wishes,
gil
Phil Jones wrote on 11/9/09 2:55 AM:

Gil,
A couple of questions.
1. See the attached. Is this paper providing the SST input to 20CRv2?
2. Do you change greenhouse gases in the run?
Apologies if these are answered elsewhere.
Do you have any pre-draft plots without subsampling to get some idea of how good the
agreement?
I'm asking these questions as I'm writing an essay for Climate Change. There are no
diagrams in this, but showing the agreement with 20CRv2 will be a nice way to finish the
paper.
Paper briefly documents the magnitude of all the problems in global temperature data -
such as SST biases, exposure issues, urbanization and site changes (in order of
importance). Site changes for global averages are the least important. Trying to point
to a few home truths to skeptics who keep on going on about the land data.
Cheers
Phil
At 15:39 03/11/2009, Gil Compo wrote:

Phil,
Already calculated. We don't suffer from some of the issues that you and Adrian raised
because we use only surface pressure.
In the Northern Hemisphere extratropics, the agreement with the various (yours, GISTEMP,
NOAA) thermometer-based near surface T is high, but in the Tropics and Southern
Hemisphere, there are discrepancies, particularly over Africa and South America. The
20CRv2 does not have the intensity of the Siberia warming.
There are also discrepancies in the WWII period. I have not subset the reanalysis to
correspond to a particular dataset's missing mask as all 3 have different coverages.
I'll be making plots for the paper (with a draft coming) soon.
best wishes,
gil
[2]P.Jones@uea.ac.uk wrote on 11/3/09 3:37 AM:

Gil,
I'm sitting in a meeting in Bristol with Rob Allan. We've
had a
thought. When you finish v2 will you be quickly calculating the global
T average for the 1891-2006 period? Do you expect this to look like the
real global T, or do you expect it to not show the longer timescale
change that NCEP from 1948 showed?

I can send a paper with Adrian Simmons from JGR in 2004 on
this when
I'm back in Norwich tomorrow.

Cheers
Phil



Dear Colleagues,

Courtesy of the NOAA Earth System Research Laboratory Physical Sciences
Division and University of Colorado CIRES Climate Diagnostics Center, at

[3]ftp://ftp.cdc.noaa.gov/Datasets/20thC_Rean/provisionalV2/ ,
please find temporary netCDF files from the 20th Century Reanalysis
version 2 (1891-2006). These yearly files are for the ensemble mean
analysis (means) and ensemble standard deviation (spreads) of selected
variables. Colleagues from organizations contributing to the 20th
Century Reanalysis version 2 or the International Surface Pressure
Databank version2.2, the observational input dataset, are welcome to
investigate these preliminary files. Colleagues on the Atmospheric
Circulation Reconstructions over the Earth Working Group 3
Verification and Validation of reanalyses are also welcome to begin
working with these files.

We are working with our distribution partners at the National Center for
Atmospheric Research, the National Oceanic and Atmospheric
Administration (NOAA) Earth System Research Laboratory and NOAAs
National Climatic Data Center on wider availability and documentation.
A rough draft of important documentation is attached.

Also, please see our new homepage at

[4]http://www.esrl.noaa.gov/psd/data/20thC_Rean/ which includes access
to
images of 6-hourly sea level pressure and 500 geopotential maps
generated from the version 2 data.

When production is complete, the 20CR version 2 will span 1871 to
present.

The references for the dataset are
Compo, G.P., J.S. Whitaker, P.D. Sardeshmukh, N. Matsui, R.J. Allan,
X. Yin,B.E. Gleason, R.S. Vose, G. Rutledge, P. Bessemoulin, S.
Br�nnimann, M. Brunet, R.I. Crouthamel, A.N. Grant, P.Y. Groisman, P.D.
Jones, M. Kruk, A.C. Kruger, G.J. Marshall, M. Maugeri, H.Y. Mok, �.
Nordli, T.F. Ross, R.M. Trigo, X.L. Wang, S.D. Woodruff, S.J. Worley,
2009: The Twentieth Century Reanalysis Project. Quarterly J. Roy. Met.
Soc., in preparation.
Compo, G.P., J.S. Whitaker, P.D. Sardeshmukh, 2008: The 20th Century
Reanalysis Project. Third WCRP International Conference on Reanalysis,
28 January 2008, Tokyo, Japan

<
[5]http://wcrp.ipsl.jussieu.fr/Workshops/Reanalysis2008/Documents/V5-511_ea.pdf
>.
Compo,G.P., J.S. Whitaker, and P.D. Sardeshmukh, 2006: Feasibility of
a 100 year reanalysis using only surface pressure data. Bull. Amer. Met.
Soc., 87, 175-190.
Whitaker, J.S., G.P.Compo, X. Wei, and T.M. Hamill 2004: Reanalysis
without radiosondes using ensemble data assimilation. Mon. Wea. Rev.,
132, 1190-1200.
Please let us know of any questions about the dataset. And, thank you
for your contributions to its development.

Best wishes,
Gil Compo
[6]<compo@colorado.edu>
Jeffrey S. Whitaker
[7]
<Jeffrey.S.WhitakeratXYZxyza.gov>
20th Century Reanalysis Project leads

--
+++++++++++++++++++++++++++++++++++++++++++++++++++
Gil Compo, Research Scientist, CIRES
University of Colorado

Mail : CIRES Climate Diagnostics Center
NOAA Physical Sciences Division
Earth System Research Laboratory
325 Broadway R/PSD1, Boulder, CO 80305-3328
Email: [8]compo@colorado.edu
Phone: (303) 497-6115 Fax: (303) 497-6449

[9]http://www.esrl.noaa.gov/psd/people/gilbert.p.compo
+++++++++++++++++++++++++++++++++++++++++++++++++++
"Stop and consider the wondrous works of God."
Job 37:34






--
+++++++++++++++++++++++++++++++++++++++++++++++++++
Gil Compo, Research Scientist, CIRES
University of Colorado

Mail : CIRES Climate Diagnostics Center
NOAA Physical Sciences Division
Earth System Research Laboratory
325 Broadway R/PSD1, Boulder, CO 80305-3328
Email: [10]compo@colorado.edu
Phone: (303) 497-6115 Fax: (303) 497-6449

[11]http://www.esrl.noaa.gov/psd/people/gilbert.p.compo
+++++++++++++++++++++++++++++++++++++++++++++++++++
"Stop and consider the wondrous works of God."
Job 37:34

Prof. Phil Jones
Climatic Research Unit Telephone +44 (0) 1603 592090
School of Environmental Sciences Fax +44 (0) 1603 507784
University of East Anglia
Norwich Email [12]p.jones@uea.ac.uk
NR4 7TJ
UK
----------------------------------------------------------------------------


--
+++++++++++++++++++++++++++++++++++++++++++++++++++
Gil Compo, Research Scientist, CIRES
University of Colorado

Mail : CIRES Climate Diagnostics Center
NOAA Physical Sciences Division
Earth System Research Laboratory
325 Broadway R/PSD1, Boulder, CO 80305-3328
Email: [13]compo@colorado.edu
Phone: (303) 497-6115 Fax: (303) 497-6449
[14]http://www.esrl.noaa.gov/psd/people/gilbert.p.compo
+++++++++++++++++++++++++++++++++++++++++++++++++++
"Stop and consider the wondrous works of God."
Job 37:34

Prof. Phil Jones
Climatic Research Unit Telephone +44 (0) 1603 592090
School of Environmental Sciences Fax +44 (0) 1603 507784
University of East Anglia
Norwich Email p.jonesatXYZxyz.ac.uk
NR4 7TJ
UK
----------------------------------------------------------------------------

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