Amarasinghe, N.

Platnick, S.

NASA Technical Reports Server

Climate Data Records: A MODIS Perspective   
S. Platnick1, N. Amarasinghe2, and the MODIS Atmosphere Team 
 
1 NASA GSFC, 2 SSAI  
Workshop on Observations & 
Modeling of Aerosol/Cloud Properties 
for Climate Studies 
Paris, 12-14 Sept 2011 
https://ntrs.nasa.gov/search.jsp?R=20120002318 2019-08-30T19:06:07+00:00Z
Outline: 
▼  Global Analyses 
▶  Trends 
▶  ENSO Correlations  
▶  Some Lessons-Learned 
Platnick, Paris Wkshop, 12 Sept 2011 
Outline: 
▼  Global Analyses 
▼  Trends 
▶  Time-to-Detection vs. grid size 
▶  Example trends, instrument artifacts 
▶  ENSO Correlations  
▶  Some Lessons-Learned 
Platnick, Paris Wkshop, 12 Sept 2011 
Motivation 
!  Trends 
–  For observed MODIS temporal variability on regional scales, what is the 
expected “time to detection” for a given trend?  
–  Consistency between Terra and Aqua MODIS? Lack of consistency traced 
to instrument differences? Statistically significant regional trends found? 
!  Sensitivity of retrievals to interannual (low frequency) climate 
variability, e.g., ENSO 
–  Correlation of atmosphere properties to ENSO useful for climate model 
evaluation (e.g., GFDL AM3 cloud fields) 
–  To what extent can ENSO responses alias into trend observations? 
!  Datasets and Analysis 
–  Monthly mean anomalies derived from archived MODIS Atmosphere 
Team Terra and Aqua monthly Level-3 aggregations 
–  Analyses for various equal-angle grids, from 1° (native Level-3 resolution) 
to regional and zonal  
–  All analysis includes effects of data set temporal correlations (“order 1” 
autocorrelation for trend calculations) 
Platnick, Paris Wkshop, 12 Sept 2011 
0 5 10 15 20
!y
0
2
4
6
8
10
%
 t
re
n
d
/d
e
c
5 1
0
10
20
20
30
30
40
40
50
50
n*(yrs) required to detect the trend
Weatherhead Equation (constant = 3.3)
example : n* = 16.3 yrs, with ! = 10%, and "=5%/dec
Number of Years Required to Detect a Trend 
(90% prob. of detecting a trend to a 0.05 statistical level, no autocorrelation: 
Tiao et al., 1990; Weatherhead et  al., 1998) 
Tr
en
d/
de
ca
de
 (%
) 
~17yrs 
Variability in monthly residual time series !y/⟨y⟩ (%) ^ 
Platnick, Paris Wkshop, 12 Sept 2011 
Time Required for Detection of 5%/decade Trend 
(90% prob. of detecting a 0.05 statistical significance,  
from 10 yr monthly anomaly variability w/autocorrelation correction) 
0 40 yrs 20 30 10 
0 90E 180 90W 0
-90
-45
0
45
90
  0
 10
 20
 30
 40
0 90E 180 90W 0
-90
-45
0
45
90
  0
 10
 20
 30
 40
[ N_STAR (omega = 5%/decade ]
Cloud_Optical_Thickness_Liquid N* (! = 5%/dec)
Cloud_Optical_Thickness_Liquid N* (! = 5%/dec)
Time Series, Monthly :JUL, 2000 to JUN, 2010
 5% significance level
smoothing(NO), autocorrelaion(YES)
10° bins 
Platnick, Paris Wkshop, 12 Sept 2011 
Time Required for Detection of 5%/decade Trend 
(90% prob. of detecting a 0.05 statistical significance,  
from 10 yr monthly anomaly variability w/autocorrelation correction) 
0 40 yrs 20 30 10 
0 90E 180 90W 0
-90
-45
0
45
90
  0
 10
 20
 30
 40
0 90E 180 90W 0
-90
-45
0
45
90
  0
 10
 20
 30
 40
[ N_STAR (omega = 5%/decade ]
Cloud_Optical_Thickness_Liquid N* (! = 5%/dec)
Cloud_Optical_Thickness_Liquid N* (! = 5%/dec)
Time Series, Monthly :JUL, 2000 to JUN, 2010
 5% significance level
smoothing(NO), autocorrelaion(YES)
20° bins 
Platnick, Paris Wkshop, 12 Sept 2011 
Time Required for Detection of 5%/decade Trend 
(90% prob. of detecting a 0.05 statistical significance,  
from 10 yr monthly anomaly variability w/autocorrelation correction) 
0 40 yrs 20 30 10 
0 90E 180 90W 0
-90
-45
0
45
90
  0
 10
 20
 30
 40
0 90E 180 90W 0
-90
-45
0
45
90
  0
 10
 20
 30
 40
[ N_STAR (omega = 5%/decade ]
Cloud_Optical_Thickness_Liquid N* (! = 5%/dec)
Cloud_Optical_Thickness_Liquid N* (! = 5%/dec)
Time Series, Monthly :JUL, 2000 to JUN, 2010
 5% significance level
smoothing(NO), autocorrelaion(YES)
30° bins 
Platnick, Paris Wkshop, 12 Sept 2011 
Time Required for Detection of 5%/decade Trend 
(90% prob. of detecting a 0.05 statistical significance,  
from 10 yr monthly anomaly variability w/autocorrelation correction) 
0 40 yrs 20 30 10 
0 90E 180 90W 0
-90
-45
0
45
90
  0
 10
 20
 30
 40
0 90E 180 90W 0
-90
-45
0
45
90
  0
 10
 20
 30
 40
[ N_STAR (omega = 5%/decade ]
Cloud_Fraction_Day N* (! = 5%/dec)
Cloud_Fraction_Day N* (! = 5%/dec)
Time Series, Monthly :JUL, 2000 to JUN, 2010
 5% significance level
smoothing(NO), autocorrelaion(YES)
Optical_Thickness_Liquid N* (! = 5%/dec)
Optical_Thickness_Liquid N* (! = 5%/dec)
AOD_Land_A d_Ocean N* (! = 5%/dec)
AOD_Land_A d_Ocean N* (! = 5%/dec)
Yearly :JUL, 20  to JUN, 2010
30° bins 
Platnick, Paris Wkshop, 12 Sept 2011 
0 90E 180 90W 0
-90
-45
0
45
90
  -20.0
  -10.0
    0.0
   10.0
   20.0
0 90E 180 90W 0
-90
-45
0
45
90
  -20.0
  -10.0
    0.0
   10.0
   20.0
[ %b0 (per decade) ]
TERRA CF (C51) anomaly (CLOUD MASK) TREND (TOTAL)
Time Series, Monthly :JUL, 2000 to JUN, 2010
 5% significance level
0 1.0 0.5 
Cloud Fraction from 
MODIS mask, Terra  
(10° binning, daytime 
observations only) 
!20 "20 0 
Annual Mean Fraction (July  2000 – June 2001) 
Cloud Fraction Trends 
(monthly anomalies, July  2000 – June 2010) 
%/decade 
Trends Masked by Significance Level ! 0.05 
(w/autocorrelation correction in t-test)  
0 90E 180 90W 0
-90
-45
0
45
90
 0.0
 0.5
 1.0
0 90E 180 90W 0
-90
-45
0
45
90
 0.0
 0.5
 1.0
[ Annual mean ]
TERRA CF (C51) CLOUD MASK 
JUL, 2000 to JUN, 2001
0 90E 180 90W 0
-90
-45
0
45
90
  -20.0
  -10.0
    0.0
   10.0
   20.0
0 90E 180 90W 0
-90
-45
0
45
90
  -20.0
  -10.0
    0.0
   10.0
   20.0
[ %b0 (per decade) ]
TERRA CF (C51) anomaly (CLOUD MASK) TREND (TOTAL)
Time Series, Monthly :JUL, 2000 to JUN, 2010
 5% significance level ~8% of grid boxes 
Platnick, Paris Wkshop, 12 Sept 2011 
MODIS Cloud Optical Thickness Trends, Aqua vs. Terra 
(water clouds, 10° binning) 
Platnick, Paris Wkshop, 12 Sept 2011 
Trends Masked by Significance Level ! 0.05 
(w/autocorrelation correction in t-test)  
0 90E 180 90W 0
-90
-45
0
45
90
  -20.0
  -10.0
    0.0
   10.0
   20.0
0 90E 180 90W 0
-90
-45
0
45
90
  -20.0
  -10.0
    0.0
   10.0
   20.0
[ %b0 (per decade) ]
TERRA ! (C51) anomaly (LIQUID) TREND (TOTAL)
Time Series, Monthly :JUL, 2000 to JUN, 2010
 5% significance level
!20 "20 0 
%/decade 
Terra 
(monthly anomalies, July  2000 – June 2010) 
0 90E 180 90W 0
-90
-45
0
45
90
  -20.0
  -10.0
    0.
   10.0
   20.0
0 90E 180 90W 0
-90
-45
0
45
90
  -20.0
  -10.0
    0.
   10.0
   20.0
[ %b0 (per decade) ]
AQUA ! (C51) anomaly (LIQUID) TREND (TOTAL)
Time Series, Monthly :JUL, 2002 to JUN, 2010
 5% significance level
Aqua 
(monthly anomalies, July  2002 – June 2010) 
Outline: 
▼  Global Analyses 
▶  Trends 
▼  ENSO Correlations 
▶  Aliasing into trends? 
▶  Some Lessons-Learned 
Platnick, Paris Wkshop, 12 Sept 2011 
ENSO3.4 SST Anomaly Index 
(avg. temperature in a box in east-central equatorial Pacific) 
Aqua 
Terra 
Platnick, Paris Wkshop, 12 Sept 2011 
0 90E 180 90W 0
-90
-45
0
45
90
 -6.0
 -5.0
 -4.0
 -3.0
 -2.0
 -1.0
  0.0
  1.0
  2.0
  3.0
  4.0
  5.0
  6.0
0 90E 180 90W 0
-90
-45
0
45
90
 -6.0
 -5.0
 -4.0
 -3.0
 -2.0
 -1.0
  0.0
  1.0
  2.0
  3.0
  4.0
  5.0
  6.0
[ LAG (months) ]
AQUACF-HIGH  (C51) anomaly(CLOUD MASK) and Ninio 3.4 ENSO index
For extreme lag correlation 
Time Series: July, 2002 - January, 2011
 1% significance level
 5% significance level
smoothing(NO), autocorrelaion(YES)
Lag (months) 
Modified Chen et al., 2007 
 
[red => cloud response lags  
E3.4 index; blue => cloud 
response precedes index] 
0 90E 180 90W 0
-90
-45
0
45
90
 -0.8
 -0.5
 -0.3
  0.0
  0.3
  0.5
  0.8
0 90E 180 90W 0
-90
-45
0
45
90
 -0.8
 -0.5
 -0.3
  0.0
  0.3
  0.5
  0.8
[ R ]
AQUACF-HIGH  (C51) anomaly(CLOUD MASK) and Ninio 3.4 ENSO index
For extreme lag correlation 
Time Series: July, 2002 - January, 2011
 1% significance level
 5% significance level
smoothing(NO), autocorrelaion(YES)
Hi h Cloud Amount Correlation 
High Cloud Amount 
Example ENSO3.4 vs. MODIS Monthly Anomaly Correlation 
1° bins, masked by 1% statistical sig., July 2002–Jan 2011 
Platnick, Paris Wkshop, 12 Sept 2011 
0 90E 180 90W 0
-90
-45
0
45
90
-110.00
 -55.00
   0.00
  55.00
 110.00
0 90E 180 90W 0
-90
-45
0
45
90
-110.00
 -55.00
   0.00
  55.00
 110.00
[ b = ∆P/∆N3.4 (hPa/ °C) ]
AQUA CT PRESSURE (C51) anomaly and Ninio 3.4 ENSO index
For extreme lag correlation 
Time Series: July, 2002 - January, 2011
 1% significance level
 5% significance level
smoothing(NO), autocorrelaion(YES)
0 90E 180 90W 0
-90
-45
0
45
90
 -0.20
 -0.10
  0.00
  0.10
  0.20
0 90E 180 90W 0
-90
-45
0
45
90
 -0.20
 -0.10
  0.00
  0.10
  0.20
[ b = ∆CF/∆N3.4 (per °C) ]
AQUACF-HIGH  (C51) anomaly(CLOUD MASK) and Ninio 3.4 ENSO index
For extreme lag correlation 
Time Series: July, 2002 - January, 2011
 1% significance level
 5% significance level
smoothing(NO), autocorrelaion(YES)
High Cloud Amount 
dfc/dT (K-1) 
Cloud-top Pressure 
dpc/dT (hPa-K-1) 
High Cloud Amount and Pressure: Derived Regression Slopes 
Example ENSO3.4 vs. MODIS Monthly Anomaly Correlation 
1° bins, masked by 1% statistical sig., July 2002–Jan 2011 
Platnick, Paris Wkshop, 12 Sept 2011 
0 90E 180 90W 0
-90
-45
0
45
90
-110.00
 -55.00
   0.00
  55.00
 110.00
0 90E 180 90W 0
-90
-45
0
45
90
-110.00
 -55.00
   0.00
  55.00
 110.00
[ b = ∆P/∆N3.4 (hPa/ °C) ]
AQUA CT PRESSURE (C51) anomaly and Ninio 3.4 ENSO index
For extreme lag correlation 
Time Series: July, 2002 - January, 2011
 1% significance level
 5% significance level
smoothing(NO), autocorrelaion(YES)
0 90E 180 90W 0
-90
-45
0
45
90
 -0.20
 -0.10
  0.00
  0.10
  0.20
0 90E 180 90W 0
-90
-45
0
45
90
 -0.20
 -0.10
  0.00
  0.10
  0.20
[ b = ∆CF/∆N3.4 (per °C) ]
AQUACF-HIGH  (C51) anomaly(CLOUD MASK) and Ninio 3.4 ENSO index
For extreme lag correlation 
Time Series: July, 2002 - January, 2011
 1% significance level
 5% significance level
smoothing(NO), autocorrelaion(YES)
High Cloud Amount 
dfc/dT (K-1) 
Cloud-top Pressure 
dpc/dT (hPa-K-1) 
High Cloud Amount and Pressure: Derived Regression Slopes 
Example ENSO3.4 vs. MODIS Monthly Anomaly Correlation 
1° bins, masked by 1% statistical sig., July 2002–Jan 2011 
GFDL AM3 high cloud amount regressed to NINO3  
(courtesy Andrew Wittenberg) 
±0.24 K-1 
Platnick, Paris Wkshop, 12 Sept 2011 
ENSO component of trend  
derived from correlation 
regression slope 
(masked by trend & ENSO3.4 
correlation sig. < 0.05) 
 
0 90E 180 90W 0
-90
-45
0
45
90
-50.00
-25.00
  0.00
 25.00
 50.00
0 90E 180 90W 0
-90
-45
0
45
90
-50.00
-25.00
  0.00
 25.00
 50.00
[ %b per decade ]
AQUA CF-HIGH (C51) anomaly (CLOUD MASK) TREND (ENSO COMPONENT)
For extreme lag correlation 
Time Series, Monthly :JUL, 2002 to JUN, 2010
 1% significance level
 5% significance level (trend + r)
smoothing(NO), autocorrelaion(YES)
0 90E 180 90W 0
-90
-45
0
45
90
  -50.0
  -25.0
    0.0
   25.0
   50.0
0 90E 180 90W 0
-90
-45
0
45
90
  -50.0
  -25.0
    0.0
   25.0
   50.0
[ %b0 (per decade) ]
AQUA CF-HIGH (C51) anomaly (CLOUD MASK) TREND (TOTAL)
Time Series, Monthly :JUL, 2002 to JUN, 2010
 5% significance level
0 90E 180 90W 0
-90
-45
0
45
90
  -50.0
  -25.0
    0.0
   25.0
   50.0
[ %b0 (per decade) ]
AQUA CF-HIGH (C51) anomaly (CLOUD MASK) TREND (TOTAL)
Time Series, Monthly :JUL, 2002 to JUN, 2010
 5% significance level(trend only)
High Cloud Amount 
Example ENSO3.4 Component of MODIS Trend (from Monthly Anomalies) 
Aqua, 1° bins, July 2002–Jun 2010 
Platnick, Paris Wkshop, 12 Sept 2011 
MODIS Aqua Trend (%/dec) 
July 2002–Jun 2010 
(masked by stat. sig. <0.05) 
 
0 90E 180 90W 0
-90
-45
0
45
90
-50.00
-25.00
  0.00
 25.00
 50.00
0 90E 180 90W 0
-90
-45
0
45
90
-50.00
-25.00
  0.00
 25.00
 50.00
[ %b per decade ]
TERRA CF-HIGH (C51) anomaly (CLOUD MASK) TREND (ENSO COMPONENT)
For extreme lag correlation 
Time Series, Monthly :JUL, 2002 to JUN, 2010
 1% significance level
 5% significance level (trend + r)
smoothing(NO), autocorrelaion(YES)
0 90E 180 90W 0
-90
-45
0
45
90
  -50.0
  -25.0
    0.0
   25.0
   50.0
0 90E 180 90W 0
-90
-45
0
45
90
  -50.0
  -25.0
    0.0
   25.0
   50.0
[ %b0 (per decade) ]
TERRA CF-HIGH (C51) anomaly (CLOUD MASK) TREND (TOTAL)
Time Series, Monthly :JUL, 2002 to JUN, 2010
 5% significance level(trend only)
High Cloud Amount 
Example ENSO3.4 Component of MODIS Trend (from Monthly Anomalies) 
Terra, 1° bins, July 2002–Jun 2010 
MODIS Terra Trend (%/dec) 
July 2002–Jun 2010 
(masked by stat. sig. <0.05) 
 
ENSO component of trend  
derived from correlation 
regression slope 
(masked by trend & ENSO3.4 
correlation sig. < 0.05) 
 
Platnick, Paris Wkshop, 12 Sept 2011 
0 90E 180 90W 0
-90
-45
0
45
90
-50.00
-25.00
  0.00
 25.00
 50.00
0 90E 180 90W 0
-90
-45
0
45
90
-50.00
-25.00
  0.00
 25.00
 50.00
[ %b per decade ]
TERRA CF-HIGH (C51) anomaly (CLOUD MASK) TREND (ENSO COMPONENT)
For extreme lag correlation 
Time Series, Monthly :JUL, 2000 to JUN, 2010
 1% significance level
 5% significance level (trend + r)
smoothing(NO), autocorrelaion(YES)
0 90E 180 90W 0
-90
-45
0
45
90
  -50.0
  -25.0
    0.0
   25.0
   50.0
0 90E 180 90W 0
-90
-45
0
45
90
  -50.0
  -25.0
    0.0
   25.0
   50.0
[ %b0 (per decade) ]
TERRA CF-HIGH (C51) anomaly (CLOUD MASK) TREND (TOTAL)
Time Series, Monthly :JUL, 2000 to JUN, 2010
 5% significance level(trend only)
ENSO component of trend  
derived from correlation 
regression slope 
(masked by trend & ENSO3.4 
correlation sig. < 0.05) 
 
High Cloud Amount 
MODIS Terra Trend (%/dec) 
July 2000–Jun 2010 
(masked by stat. sig. <0.05) 
 
Example ENSO3.4 Component of MODIS Trend (from Monthly Anomalies) 
Terra, 1° bins, July 200 –Jun 2010 
Platnick, Paris Wkshop, 12 Sept 2011 
ENSO3.4 Aliasing Into Trends 
Number of years for ENSO trend to decay to less than some value?  
0 10 20 30 40
–2
–1
0
1
2
years since start of record
EN
SO
3.
4 
tre
nd
 (K
/d
ec
ad
e)
cumulative by year from January in given year up to 2010
start: 1975
start: 1970
start: 1965
±0.3K/dec ⇒ 
15-30 yrs 
Platnick, Paris Wkshop, 12 Sept 2011 
Outline: 
▼  Global Analyses 
▶  Trends 
▶  ENSO Correlations  
▶  Some Lessons-Learned 
Platnick et al., CDR, 2 Aug 2011 
Calibration/Validation  
(L1 and L2) 
L2 (pixel, swath) &  
L3 (gridded statistics) 
algorithms 
Instrument prelaunch &  
on-orbit characterization, 
L1 algorithms 
(re-)processing 
and test system 
Archive, 
Distribution, 
Documentation users 
A Coordinated System/Infrastructure of Elements is 
Required for Production and Sustainability of Climate Records 
Ancillary 
data sets 
Platnick, Paris Wkshop, 12 Sept 2011 
Thank you! 
Platnick, Paris Wkshop, 12 Sept 2011 


Climate Data Records: A MODIS Perspective

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