Projected Changes in Nile Flows: RCM Results
description
Transcript of Projected Changes in Nile Flows: RCM Results
![Page 1: Projected Changes in Nile Flows: RCM Results](https://reader036.fdocuments.in/reader036/viewer/2022062501/568164d5550346895dd70c93/html5/thumbnails/1.jpg)
Projected Changes in Nile Flows: RCM Results
Mid-Term WorkshopClimate Change Risk Management
Programme Forecasting & IWRM Component
Prepared by: Nile Forecast Center
![Page 2: Projected Changes in Nile Flows: RCM Results](https://reader036.fdocuments.in/reader036/viewer/2022062501/568164d5550346895dd70c93/html5/thumbnails/2.jpg)
Outline
1. Modeling Climate Change Impacts
2. Pervious Studies on the Nile
3. Study Methodology
4. Results
5. Conclusions
![Page 3: Projected Changes in Nile Flows: RCM Results](https://reader036.fdocuments.in/reader036/viewer/2022062501/568164d5550346895dd70c93/html5/thumbnails/3.jpg)
Modeling Climate Change Impacts Methodology and Uncertainty Cascade
Emissions
Concentrations
Radiative Forcing
Global Climate Models
Regional Details (Downscaling)
Impact Models (e.g. Hydrology) Obs
erva
tions
![Page 4: Projected Changes in Nile Flows: RCM Results](https://reader036.fdocuments.in/reader036/viewer/2022062501/568164d5550346895dd70c93/html5/thumbnails/4.jpg)
The Nile Basin
Large area (2.9 x 106 km2) Low specific discharge Spans several climate
regions Variable topography High runoff variability High Sensitivity to Climate
Mongalla
Jinja
Pakwach
Diem
Roseires
Sennar
Khartoum
Malakal
Atbara
KhashmEl-Girba
Aswan
Dongola
Mogren
Hillet Doleib
Masindi
Cairo
LakeNo
TANZAN IABU RU NDI
Gabal Awlia
Paara
-5
0
5
10
15
20
25
30
35
20 25 30 35 40
EGY PT
ETH IOPIA
D.R. CONGO
RWANDA
L IBY A
CENTRALAF RICAN
REP.
U GANDA
SU DAN
ERITRIACHAD
K EN Y A
![Page 5: Projected Changes in Nile Flows: RCM Results](https://reader036.fdocuments.in/reader036/viewer/2022062501/568164d5550346895dd70c93/html5/thumbnails/5.jpg)
Lake Nasser Flood & Drought Control Project (2008)
Previous Studies (1)
– 6 Transient scenarios (3 GCMs x 2 Emission Scenarios)
– Statistically downscaled using a spatio-temporal weather generator
– Changes at Dongola from 2010-2100
0
20
40
60
80
100
120
Base 2010s 2020s 2030s 2040s 2050s 2060s 2070s 2080s 2090s
Tota
l Ann
ual F
low
(BC
M)
HadCM3 A2 HadCM3 B2CGCM2 A2 CGCM2 B2ECHAM4 A2 ECHAM4 B2OBS Base
Elshamy, M.E., Sayed, M.A.-A. and Badwy, B., 2009. Impacts of climate change on Nile flows at Dongola using statistically downscaled GCM scenarios. Nile Water Science & Engineering Magazine 2: 1-14
![Page 6: Projected Changes in Nile Flows: RCM Results](https://reader036.fdocuments.in/reader036/viewer/2022062501/568164d5550346895dd70c93/html5/thumbnails/6.jpg)
Previous Studies (2)Elshamy et al. (2009)– 17 GCMs x A1B
scenario– Statistically
downscaled using Bias Correction Method
– Blue Nile Flow Changes: -60% to +45%
0
2
4
6
8
10
12
14
16
18
20
22
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Flow
(BCM
)
Ensemble Mean 2081-98
Observed 1961-90
Elshamy, M.E., Seierstad, I.A. and Sorteberg, A., 2009. Impacts of climate change on Blue Nile flows using bias-corrected GCM scenarios. Hydrol. Earth Syst. Sci., 13(5): 551-565.
![Page 7: Projected Changes in Nile Flows: RCM Results](https://reader036.fdocuments.in/reader036/viewer/2022062501/568164d5550346895dd70c93/html5/thumbnails/7.jpg)
MethodologyCoarse Scale GCM Boundary Conditions
RCM Downscaling
Fine-Scale Climate(Baseline 1950-2000 & Future 2020-2050)
Calculate Delta Change Factors (DCFs)
Modify Baseline Data (1989-2007) using DCFs
Determine Hydrological Impacts (NFS)
![Page 8: Projected Changes in Nile Flows: RCM Results](https://reader036.fdocuments.in/reader036/viewer/2022062501/568164d5550346895dd70c93/html5/thumbnails/8.jpg)
Methodology: Why RCM?RCM GCM
• Higher Resolution: Better Representation of shoreline and terrain
• Physical Model: Consistent Climate Elements
![Page 9: Projected Changes in Nile Flows: RCM Results](https://reader036.fdocuments.in/reader036/viewer/2022062501/568164d5550346895dd70c93/html5/thumbnails/9.jpg)
Methodology: Ensemble SelectionEmission Scenario A1B
![Page 10: Projected Changes in Nile Flows: RCM Results](https://reader036.fdocuments.in/reader036/viewer/2022062501/568164d5550346895dd70c93/html5/thumbnails/10.jpg)
1
Results: Rainfall Changes - RatiosJan2 3 4 5 6
Black: Ratio cannot be calculated White: Off Scale (>3)
![Page 11: Projected Changes in Nile Flows: RCM Results](https://reader036.fdocuments.in/reader036/viewer/2022062501/568164d5550346895dd70c93/html5/thumbnails/11.jpg)
1
Results: Rainfall Changes - RatiosAug2 3 4 5 6
Black: Ratio cannot be calculated White: Off Scale (>3)
![Page 12: Projected Changes in Nile Flows: RCM Results](https://reader036.fdocuments.in/reader036/viewer/2022062501/568164d5550346895dd70c93/html5/thumbnails/12.jpg)
1
Results: Temperature Changes - Diffs
Jan2 3 4 5 6
![Page 13: Projected Changes in Nile Flows: RCM Results](https://reader036.fdocuments.in/reader036/viewer/2022062501/568164d5550346895dd70c93/html5/thumbnails/13.jpg)
1
Results: Temperature Changes - Diffs
Aug2 3 4 5 6
![Page 14: Projected Changes in Nile Flows: RCM Results](https://reader036.fdocuments.in/reader036/viewer/2022062501/568164d5550346895dd70c93/html5/thumbnails/14.jpg)
Results: PET Changes
NFS Selected Scenario
![Page 15: Projected Changes in Nile Flows: RCM Results](https://reader036.fdocuments.in/reader036/viewer/2022062501/568164d5550346895dd70c93/html5/thumbnails/15.jpg)
Hydrological Changes: Blue Nile@Diem
1 2 3 4 5 6 7 8 9 10 11 12
-50%
-40%
-30%
-20%
-10%
0%
10%
20%
30%
40%
50%
Rai
nfal
l Cha
nges
1 2 3 4 5 6 7 8 9 10 11 12
-50%
-40%
-30%
-20%
-10%
0%
10%
20%
30%
40%
50%
PET
Cha
nges
1 2 3 4 5 6 7 8 9 10 11 12
-50%
-40%
-30%
-20%
-10%
0%
10%
20%
30%
40%
50%
Flow
Cha
nges
![Page 16: Projected Changes in Nile Flows: RCM Results](https://reader036.fdocuments.in/reader036/viewer/2022062501/568164d5550346895dd70c93/html5/thumbnails/16.jpg)
Hydrological Changes: White Nile@Malakal
1 2 3 4 5 6 7 8 9 10 11 12
-40%
-30%
-20%
-10%
0%
10%
20%
30%
40%
Rai
nfal
l Cha
nges
1 2 3 4 5 6 7 8 9 10 11 12
-40%
-30%
-20%
-10%
0%
10%
20%
30%
40%
PET
Cha
nges
1 2 3 4 5 6 7 8 9 10 11 12
-40%
-30%
-20%
-10%
0%
10%
20%
30%
40%
Flow
Cha
nges
![Page 17: Projected Changes in Nile Flows: RCM Results](https://reader036.fdocuments.in/reader036/viewer/2022062501/568164d5550346895dd70c93/html5/thumbnails/17.jpg)
Conclusions • Expected ranges for changes in rainfall,
temperature, and PET are smaller than previous studies
• Changes in flows: -19% to +29% for the Blue Nile (Diem)-8% to +10% for the White Nile (Malakal)
• RCM provides a viable downscaling methodology
• RCM results confirm the uncertainty regarding the direction of change for rainfall and flow
• RCM reduced the uncertainty bandwidth but care must be taken that not all sources are included
![Page 18: Projected Changes in Nile Flows: RCM Results](https://reader036.fdocuments.in/reader036/viewer/2022062501/568164d5550346895dd70c93/html5/thumbnails/18.jpg)
Way Forward Collaboration within the Nile Basin to exchange data
and experience Nile countries need to Adapt to Flow Changes – In
addition to population growth– Flexibility in Water Management to face uncertainty– No regret step-wise adaptation plans
Translating Climate impacts into hydrological agricultural socio-economic, hydropower, … impacts
Further research: Expansion to other Emission Scenarios, RCMs, etc to better characterize the uncertainty, uncertainty propagation to decision making – adaptation planning
![Page 19: Projected Changes in Nile Flows: RCM Results](https://reader036.fdocuments.in/reader036/viewer/2022062501/568164d5550346895dd70c93/html5/thumbnails/19.jpg)