Seasonal Degree Day Outlooks
-
Upload
judah-weber -
Category
Documents
-
view
36 -
download
0
description
Transcript of Seasonal Degree Day Outlooks
![Page 1: Seasonal Degree Day Outlooks](https://reader035.fdocuments.in/reader035/viewer/2022062304/56813061550346895d962d06/html5/thumbnails/1.jpg)
Seasonal Degree Day Outlooks
David A. Unger
Climate Prediction Center
Camp Springs, Maryland
![Page 2: Seasonal Degree Day Outlooks](https://reader035.fdocuments.in/reader035/viewer/2022062304/56813061550346895d962d06/html5/thumbnails/2.jpg)
Definitions
HDD = 65 – t t < 65 F
CDD = t – 65 t > 65 F
HD = HDD/N CD = CDD/NT = 65+CD-HDCD = T –65 +HDt = daily mean temperature, T=Monthly or Seasonal Mean
N = Number of days in month or season
_
_ _
_ _
__
_
![Page 3: Seasonal Degree Day Outlooks](https://reader035.fdocuments.in/reader035/viewer/2022062304/56813061550346895d962d06/html5/thumbnails/3.jpg)
CPC Outlook
![Page 4: Seasonal Degree Day Outlooks](https://reader035.fdocuments.in/reader035/viewer/2022062304/56813061550346895d962d06/html5/thumbnails/4.jpg)
CPC POE Outlooks
![Page 5: Seasonal Degree Day Outlooks](https://reader035.fdocuments.in/reader035/viewer/2022062304/56813061550346895d962d06/html5/thumbnails/5.jpg)
![Page 6: Seasonal Degree Day Outlooks](https://reader035.fdocuments.in/reader035/viewer/2022062304/56813061550346895d962d06/html5/thumbnails/6.jpg)
OverviewTools
Temperature FcstProb. Anom.For Tercile
(Above, Near, Below)
Temperature POE
Degree DaysHDD CDD POE
Degree DaysFlexible Region, Seasons
Forecaster Input
Model Skills, climatology
Downscaling (Regression Relationships)
Temperature POEDownscaled Temperature to Degree Day
(Climatological Relationships)
Accumulation Algorithms
Skill: Heidke .10
RPS .02
Skill: CRPS .02
CRPS Skill: CDD .05
HDD .02
Skill: CRPS .03
CRPS Skill: CDD .06
HDD .02
![Page 7: Seasonal Degree Day Outlooks](https://reader035.fdocuments.in/reader035/viewer/2022062304/56813061550346895d962d06/html5/thumbnails/7.jpg)
Temperature to Degree Days
![Page 8: Seasonal Degree Day Outlooks](https://reader035.fdocuments.in/reader035/viewer/2022062304/56813061550346895d962d06/html5/thumbnails/8.jpg)
Rescaling
FD Seasonal
FD Monthly
CD Seasonal
CD Monthly
Downscaling
Disaggregation
![Page 9: Seasonal Degree Day Outlooks](https://reader035.fdocuments.in/reader035/viewer/2022062304/56813061550346895d962d06/html5/thumbnails/9.jpg)
Downscaling
• Regression
• CD = a FD +b
Equation’s coefficients are “inflated”
(CD variance = climatological variance)
![Page 10: Seasonal Degree Day Outlooks](https://reader035.fdocuments.in/reader035/viewer/2022062304/56813061550346895d962d06/html5/thumbnails/10.jpg)
Disaggregation - Seasonal to Monthly
• Tm = a Ts + b
Regression, inflated coefficients
• Average 3 estimates
M JFM + M FMA + M MAM
3
M =
![Page 11: Seasonal Degree Day Outlooks](https://reader035.fdocuments.in/reader035/viewer/2022062304/56813061550346895d962d06/html5/thumbnails/11.jpg)
Verification note
• Continuous Ranked Probability Score
- Mean Absolute Error with provisions
for uncertainty
• Skill Score = 1. –
- Percent Improvement over climatology
Climo
CRPS
CRPS
![Page 12: Seasonal Degree Day Outlooks](https://reader035.fdocuments.in/reader035/viewer/2022062304/56813061550346895d962d06/html5/thumbnails/12.jpg)
Continuous Ranked Probability Score
![Page 13: Seasonal Degree Day Outlooks](https://reader035.fdocuments.in/reader035/viewer/2022062304/56813061550346895d962d06/html5/thumbnails/13.jpg)
.031
.023
.028 .019
.040 .036
.026 .030
.094 .103
.074 .090
.035 .030
.012 .015
1-Mo
FD CD
3-Mo
CRPS Skill Scores: Temperature
-.009 .002
-.006 -.008
.002 .001
.011 .004
.044 .038
.050 .047
.013 .016
.027 .026
.055 .059
.055 .058
.027 .029
.026 .023
.020 .021
.024 .024
.051 .045
.041 .034
.065 .055
.042 .035
High
Moderate
Low
None
Skill
.10
.05
.01
1-Month Lead, All initial times
![Page 14: Seasonal Degree Day Outlooks](https://reader035.fdocuments.in/reader035/viewer/2022062304/56813061550346895d962d06/html5/thumbnails/14.jpg)
.049
.057
.018 .016
.101 .121
.014 .076
.088 .115
.079 .111
.033 .051
.005 .003
Heating
1-Mo 12-Mo
Cooling
CRPS Skill Scores: Heating and Cooling Degree Days
-.004 .036
-.026 -.016
.009 .022
.000 -0.16
.035 .014
.045 -.003
.058 .043
.021 -.011
.090 .090
.029 .035
.114 .085
.019 .028
.047 .102
.023 .048
.040 .071
.036 .073
.044 .024
.046 .030
High
Moderate
Low
None
Skill
.10
.05
.02
![Page 15: Seasonal Degree Day Outlooks](https://reader035.fdocuments.in/reader035/viewer/2022062304/56813061550346895d962d06/html5/thumbnails/15.jpg)
Degree Day Forecast (Accumulations)
![Page 16: Seasonal Degree Day Outlooks](https://reader035.fdocuments.in/reader035/viewer/2022062304/56813061550346895d962d06/html5/thumbnails/16.jpg)
![Page 17: Seasonal Degree Day Outlooks](https://reader035.fdocuments.in/reader035/viewer/2022062304/56813061550346895d962d06/html5/thumbnails/17.jpg)
Reliability
![Page 18: Seasonal Degree Day Outlooks](https://reader035.fdocuments.in/reader035/viewer/2022062304/56813061550346895d962d06/html5/thumbnails/18.jpg)
Reliability
![Page 19: Seasonal Degree Day Outlooks](https://reader035.fdocuments.in/reader035/viewer/2022062304/56813061550346895d962d06/html5/thumbnails/19.jpg)
Conclusions
• Downscaled forecasts nearly as skillful as original temperature outlook
• Skill better in Summer than Winter
• Better understanding of season to season dependence will lead to improved forecasts for periods greater than 3-months.
![Page 20: Seasonal Degree Day Outlooks](https://reader035.fdocuments.in/reader035/viewer/2022062304/56813061550346895d962d06/html5/thumbnails/20.jpg)
Testing
• 50 – years of “perfect OCN”
Forecast = decadal mean and standard deviation• Target year is included to assure skill.• Seasonal Forecasts on Forecast Divisions supplied
How does the skill of the rescaled forecasts
compare to the original
![Page 21: Seasonal Degree Day Outlooks](https://reader035.fdocuments.in/reader035/viewer/2022062304/56813061550346895d962d06/html5/thumbnails/21.jpg)
.104
.109
.066 .057
.106 .019
.067 .077
.198 .233
.106 .135
.138 .140
.086 .067
Seasonal
FD CD
Monthly
CRPS Skill Scores – Downscaled and disaggregated
.108 .105
.061 .060
.088 .085
.061 .055
.074 .070
.052 .037
.086 .083
.061 .059
.110 .086
.066 .066
.088 .092
.063 .039
.109 .109
.058 .055
.098 .081
.061 .042
.110 .087
.074 .044
SkillHigh
Moderate
Low
None
.10
.05
.01
![Page 22: Seasonal Degree Day Outlooks](https://reader035.fdocuments.in/reader035/viewer/2022062304/56813061550346895d962d06/html5/thumbnails/22.jpg)
.104
.095
.104 .074
.106 .081
.106 .085
.198 .197
.198 .151
.138 .140
.138 .102
Heating
T DD
Cooling
CRPS Skill Scores Temperature to Degree Days
.108 .097
.108 .066
.088 .093
.088 .085
.074 .078
.074 .049
.086 .090
.086 .053
.110 .092
.110 .060
.088 -.006
.088 .070
.109 .038
.109 .090
.098 -.027
.098 .082
.110 .076
.110 .109
High
Moderate
Low
None
Skill
.10
.05
.01
![Page 23: Seasonal Degree Day Outlooks](https://reader035.fdocuments.in/reader035/viewer/2022062304/56813061550346895d962d06/html5/thumbnails/23.jpg)
Accumulation Algorithm
DD = DD + DD
Independent (I)
Dependent (D)
From Climatology
=
<
A+B
(I) (D)
A+B = A B
A+B =A B
+
+
+
2 2
A+B
A+B
<
A+B
2
A+B A B
KA+B
(I)(I)
(I) (D) =
(D)(D)K( )+