casey marinedataworkshop.ppt [read-only] · 2002-05-01 · historical marine climate data 6...
Post on 11-Aug-2020
1 Views
Preview:
TRANSCRIPT
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
1
SST Analysis By Temperature Class
Kenneth S. CaseyUCAR-NOAA/NESDIS/NODC
Peter CornillonURI/GSO
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
2
Introduction
Interests in annual-decadal SST trendsand climatology development
New method of binning anomalies
Temperature classes based on mean SST
Comparisons to traditional binningschemes
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
3
Key Results
SST analysis by temperature class…
Provides new perspective for climatologytesting and trend estimation
Finds similar trends in recent years
Extends trends further back in time
Lowers error in data-sparse years
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
4
Technique
Develop satellite-only climatology fromAVHRR Pathfinder
9 km resolution
Twice-dailyfields from 1985
Erosion filter
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
5
Technique
Erosion Filter:
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
6
Technique
Compute individual SST anomalies:• COADS (~ 88 million, 1942-)• WOA94 (~ 4 million, 1900-)• Use Reynolds, GOSTA, GISST, WOA94,
and Pathfinder climatologies
Average into temperature class bins and5-degree latitude-longitude binsApply to climatology testing and trends
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
7
Temperature Classes
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
8
Climatology Testing
Create WOA94 and COADS anomaliesfrom several different climatologiesBin by latitude band or temperatureclassFind climatology with lowest standarddeviation of anomalies…
(Casey and Cornillon, 1999)
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
9
Climatology Testing: COADS
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
10
Climatology Testing: WOA94
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
11
Climatology Testing: Latitude
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
12
Climatology Testing: Latitude
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
13
Trend Estimation
Create WOA94 and COADS anomaliesfrom AVHRR Pathfinder climatology
Average into 5° bins or temperature class
Calculate global and regional SSTtrends…
(Casey and Cornillon, 2001)
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
14
COADS Global Trend Results
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
15
WOA94 Global Trend Results
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
16
Measure relative ability of two averagingmethodsCompare mean variances and number ofobservations in monthly bins to achievesmallest standard error, _2/NEfficiency parameter = _2
5/ _2T
Determine needed NT to achieve lower_2
T/NT than _25/N5
Statistical Efficiency
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
17
Statistical Efficiency
2.221.920.52WOA94
clustered
2.472.040.49WOA94
4.731.490.67COADS
NT/ N5observed
NT/N5needed
_25/ _2
TDataset
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
18
Regional SST Trends
Determine annual anomalies in eachtemperature class or 5° bin
Average within regions
Calculate linear trends from 1960-1990
Plot and compare…
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
19
Regional SST Trends
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
20
Regional SST Trends
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
21
Subregional Trends
Bin anomalies by temperature class andplot 1960-1990 linear trends
Compare with trends calculated from 5°bins averaged latitudinally
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
22
COADS Regional Trends
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
23
WOA94 Regional Trends
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
24
COADS Regional Trends
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
25
WOA94 Regional Trends
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
26
Temperature Class Summary
AVHRR Pathfinder SST climatology
New perspective for climatology testingand trend estimation
Similar results in well-sampled years
Trends extended further back in time
Smaller error in data-sparse years
Jan 29-Feb 1, 2002Kenneth.Casey@noaa.gov
Workshop on Advances in the Use ofHistorical Marine Climate Data
27
For More Info…
Casey, K.S. and P. Cornillon (1999). Acomparison of satellite and in situ based seasurface temperature climatologies, Journal ofClimate, vol 12, no 6, pp. 1848-1863Casey, K.S. and P. Cornillon (2001). Globaland regional sea surface temperature trends,Journal of Climate, vol 14, no 18, pp. 3801-3818.PPT presentation and PDF and PS versions at:http://intra.nodc.noaa.gov/Information/kcasey
top related