Significance of Decadal Prediction Significance of Decadal Prediction for GHAfor GHA22-24 June 2009

World Bank_GFDRR ProjectGeneva, Switzerland

Fredrick SemazziNorth Carolina State University

USA

FocusFocus

Challenge of providing predicted decadal climate Challenge of providing predicted decadal climate variability & climate change information at spatial variability & climate change information at spatial scales appropriate for end-usersscales appropriate for end-users

Improved Surface Temperature Prediction for the Coming Decade from a Global Climate Model

Doug M. Smith,* Stephen Cusack, Andrew W. Colman, Chris K. Folland, Glen R. Harris, James M. Murphy

• Previous climate model projections of climate change accounted for external forcing from natural and anthropogenic sources but did not attempt to predict internally generated natural variability.

• Smith et a 2007 present a new modeling system that predicts both internal variability and externally forced changes & hence forecasts surface temperature with substantially improved skill throughout a decade, both globally and in many regions.

• This system predicts that internal variability will partially offset the anthropogenic global warming signal for the next few years.

• However, climate will continue to warm, with at least half of the years after 2009 predicted to exceed the warmest year currently on record.

GFDRR Goal#1Regional climate trends and the adequacy of global and

regional climate observations for adaptation purposes

Eastern AfricaEastern Africa Decadal Dipole Mode-basedDipole Mode-based on CMAP on CMAP 2.5 degree resolution2.5 degree resolution

-1.5

-1

-0.5

0

0.5

1

1.5

1981 1983 1985 1987 1989 1991 1993 1995 1997 1999

AFRICAN HadCRUT

+

-+

-

Eastern AfricaEastern Africa Decadal Dipole Dipole Mode-based on CMAP 2.5 degree Mode-based on CMAP 2.5 degree

resolutionresolution

Eastern AfricaEastern Africa Decadal Dipole Dipole ModeMode

(based on NASA satellite data)

+ -

Largest drying Largest drying signal over land signal over land is over Eastern is over Eastern

AfricaAfrica

Esp. Serengeti Esp. Serengeti Masai-Mara Masai-Mara

CorridorCorridor

http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17761

Increasing RainfallIncreasing Rainfall

Decreasing RainfallDecreasing Rainfall

IPCC GCM Projections Decadal Dipole Mode: Is it a fingerprint

of climate change over Eastern Africa

INFORMATION REQUIRED AT DISTRICT SCALE

Average Annual Total Rainfall (mm)(Based on Willmott Climate Dataset)

• The analysis of the data provides important The analysis of the data provides important information atinformation at district district levellevel about spatial distribution and amount of rainfallabout spatial distribution and amount of rainfall which is which is necessary for planning climate sensitive social-economic activitiesnecessary for planning climate sensitive social-economic activities

• Makes distinction between Makes distinction between aridarid and and semi-arid climatic conditions over climatic conditions over Kenya Kenya

500

500

500 1200

1200

Turkana District (arid)

Wajir District (arid)

Garissa District (arid)

Kitui District (semi-arid)

Narok District (semi-arid)

aridarid

Semi-aridSemi-arid

Climate Data

Over the arid and semi-arid regions rain-gauge data coverage is very marginal

Monitoring over these regions need to be upgraded

500

500

500 1200

1200

Turkana District (arid)

Wajir District (arid)

Garissa District (arid)

Kitui District (semi-arid)

Narok District (semi-arid)

50

50

50 100

50

Turkana District (arid)

Wajir District (arid)

Garissa District (arid)

Kitui District (semi-arid)

Narok District (semi-arid)Wil

lmo

tt -

CR

UW

illm

ott

- C

RU

Wil

lmo

tt C

lim

ato

log

yW

illm

ott

Cli

mat

olo

gy

Present Climate Data Quality is Acceptable for Social-Economic Planning at District Level but Inherent Data Uncertainties are a Limiting Factor and Need to be Reduced

Po

ten

tial

Err

ors

Po

ten

tial

Err

ors

Short RainsShort Rains

Onset/WithdrawOnset/Withdraw

one rain season

one rain season

Highly erraticHighly erratic

Examples of Applications

- Tourism(Serengeti National Park)

- Hydroelectric power generation

Owen Falls Dam at source of River Nile

- Navigation Safety over Lake Victoria

Tourism(Serengeti National Park)

Masai Mara-Serengeti Climate Anomalies Impacts on Wildebeest Migration

Masai Mara-Serengeti(2005 Drought)

Assessment shows that very late start Assessment shows that very late start of the rains was responsibleof the rains was responsible

for the 2005 disasterfor the 2005 disaster

Analysis also clearly detects the Analysis also clearly detects the severe 1998-1999 droughtsevere 1998-1999 drought

Serengeti Masai-Mara Wildebeest MigrationSerengeti Masai-Mara Wildebeest MigrationRoute and Timing is dependent on Climatic ConditionsRoute and Timing is dependent on Climatic Conditions

Best Time for Tourists to see Migration is the Crossing of Grumeti River in Western Serengeti Best Time for Tourists to see Migration is the Crossing of Grumeti River in Western Serengeti Park/Tanzania or Crossing of Mara River into Masai Mara National Park/Kenya Park/Tanzania or Crossing of Mara River into Masai Mara National Park/Kenya

[http://www.safarimappers.com/serengeti-migration.aspx[http://www.safarimappers.com/serengeti-migration.aspx

January February March April

March June July August

September October November December

Masai Mara-Serengeti Masai Mara-Serengeti Climate Anomalies Impacts on Wildebeest Climate Anomalies Impacts on Wildebeest

Migration & Tourism Industry in KenyaMigration & Tourism Industry in Kenya

• Late start of the 2005 was the primary reason for the failure of the rains over Masai Late start of the 2005 was the primary reason for the failure of the rains over Masai Mara-Serengeti rather than early withdrawMara-Serengeti rather than early withdraw

• This is region has a clear trend due to the climate change fingerprint signal; Further This is region has a clear trend due to the climate change fingerprint signal; Further increased delay of 2 weeks in the start of the rains in Kenya, which is good possibility in the increased delay of 2 weeks in the start of the rains in Kenya, which is good possibility in the next 10 years, would adversely disrupt/shift the timing of the next 10 years, would adversely disrupt/shift the timing of the wildebeest migration cycle migration cycle

• For example a two week delay in the start of the rains would put the location of the For example a two week delay in the start of the rains would put the location of the wildebeest herds deep into Tanzania. Kenya bound tourist using the climatic migration herds deep into Tanzania. Kenya bound tourist using the climatic migration calendar would miss the extravaganza altogether (see schematic for migration route)calendar would miss the extravaganza altogether (see schematic for migration route)

• Although it cannot be asserted that a collapse of this world-famous ecosystem is imminent Although it cannot be asserted that a collapse of this world-famous ecosystem is imminent based on this assessment, the climate stress could eventually undermine it beyond point of no based on this assessment, the climate stress could eventually undermine it beyond point of no return return

• Therefore baseline characterization of the local climate is important for wildlife monitoring, Therefore baseline characterization of the local climate is important for wildlife monitoring, and in the face of climate change, accurate projections are critical to assess the fate of the and in the face of climate change, accurate projections are critical to assess the fate of the future of the tourism industry in Kenya that depend on this region.future of the tourism industry in Kenya that depend on this region.

Naroc district (Masai Mara-Serengeti) impacts Naroc district (Masai Mara-Serengeti) impacts exampleexample

Climate Anomalies Impacts on Wildebeest Migration & Tourism Industry Climate Anomalies Impacts on Wildebeest Migration & Tourism Industry in Kenyain Kenya

• The late start of the rain season was the primary reason for the catastrophic failure of the rains over The late start of the rain season was the primary reason for the catastrophic failure of the rains over Masai Mara-Serengeti in 2005. Masai Mara-Serengeti in 2005. • Apparently once there is a significant delay in the start of the rainfall onset the chances of recovery Apparently once there is a significant delay in the start of the rainfall onset the chances of recovery back to normal seasonal rainfall is very unlikely.back to normal seasonal rainfall is very unlikely. • In the Masai-Mara Park tourism the movement of the rain belt is a fundamental driver of the migration of In the Masai-Mara Park tourism the movement of the rain belt is a fundamental driver of the migration of wildlife because it dictates the growth of seasonal vegetation coverwildlife because it dictates the growth of seasonal vegetation cover..• The onset of the rains around March triggers the migration of the Wildebeest population from Kenya The onset of the rains around March triggers the migration of the Wildebeest population from Kenya Masai-Mara into Serengeti in Tanzania. Masai-Mara into Serengeti in Tanzania. • A recent study (Douglas E. Musiega1, Sanga-Ngoie Kazadi, 2006) has shown that dry season migration A recent study (Douglas E. Musiega1, Sanga-Ngoie Kazadi, 2006) has shown that dry season migration routes tend toward areas with better vegetation activity, i.e., those characterized by higher NDVI routes tend toward areas with better vegetation activity, i.e., those characterized by higher NDVI gradients. gradients. • During the western trek, wetter dry seasons have the effect of delaying the wildlife movement During the western trek, wetter dry seasons have the effect of delaying the wildlife movement northwestward.northwestward. • However the variation in rainfall conditions during the rainy and dry season has no significant influence However the variation in rainfall conditions during the rainy and dry season has no significant influence on the southern trek route location because movement is dictated by hardship of the terrain rather on the southern trek route location because movement is dictated by hardship of the terrain rather vegetation which is abundantvegetation which is abundant• During the northern trek, wetter dry seasons have the effect of delaying the tendency to move westwardDuring the northern trek, wetter dry seasons have the effect of delaying the tendency to move westward• Therefore baseline characterization of the local climate is important for herds monitoring and Therefore baseline characterization of the local climate is important for herds monitoring and performance of the tourism industry in Kenya, and in the face of climate change, accurate projections will performance of the tourism industry in Kenya, and in the face of climate change, accurate projections will be criticalbe critical• It will be critical to monitor the relationship between the dipole mode (possible finger print of climate It will be critical to monitor the relationship between the dipole mode (possible finger print of climate

change) and the migration patterns as this could result in major shifts of migration patterns.change) and the migration patterns as this could result in major shifts of migration patterns.

GFDRR Goal#2: assess the adequacy and reliability of

available model-based climate projections for adaptation needs

Rainfall Projections (A2: 2071-2100 average) minus (RF: 1961-1990 average)

Oct-Dec Short Rains

Rainfall projections (A2: 2071-2100 average) minus (RF: 1961-1990 average) for the Oct-Dec short rains: (left) RegCM3 (40 km grid); (centre) 2-member FvGCM ensemble average; (right) eight IPCC GCM super ensemble average. Units, mm.

General agreement among, 40km resolution RCM, high resolution (approx 1 deg) GCM, and coarse resolution(>2 deg) IPCC GCM ensemble; however differences are critical for some end users

GFDRR Goal#3: provide qualified indications of expected climate

change for assistance in developing effective adaptation and climate risk management strategies

Aerial view of Nalubaale-Kiira Dam(Source of River Nile)

Spatial Scales Over Lake Victoria Basin for Hydro-E & Tourism

Require models that are not only of high resolution but also support the physics responsible for the critical mechanisms

Lake Victoria Basin Climate VariabilityAlgorithm for

(making lake level projections) RegCM3-POM coupled model lake surface temperature & rainfall; Anyah & Semazzi (2006)

“no trend” pre-1961 lake

levels

97-98 El Nino

Surface temperature, RH & winds; RegCM3 model verification against MODIS & NCEP (Onol & Semazzi, 2006).

MODIS (satellite) NCEP Reanalysis

RegCM3 RCM RegCM3 RCM

1961-62IO Warming

downscaling

Lake Victoria levels; gauge at source of the River Nile & satellite radar altimeter data from USDS/NASA/UMD at http://www.pecad.fas.usda.gov/cropexplorer/global_reservoir/

Water Balance model

(Tate et al, 2004)

Global NCEP January Temperature Anomaly Pattern, 2006 minus average of 2001-2005

downscaling

10.6

10.8

11

11.2

11.4

11.6

11.8

12

12.2

12.4

12.6

12.8

13

13.2

1955 1960 1965 1970 1975 1980 1985 1990 1995

modeled lake level (1 year prediction)

Actual lake level (Dec)

Current & Projected Levels of Lake VictoriaCurrent & Projected Levels of Lake Victoria

(left) Lake Victoria observed levels (blue) compared to estimates based on our modified version of Tate et al (2004) water balance model for Lake Victoria with observed rainfall from six rain gauge stations (red); (center) Lake Victoria observed levels (blue) compared to estimates based on our modified version of Tate et al (2004) water balance model for Lake Victoria with rainfall from RegCM3-20km resolution reference run (red); (right) lake levels projections (2071-2100) based on rainfall input from RegCM3 (20km grid) A2 simulation. Since the initial level of the lake for 2071 is unknown, we assume multiple initial conditions for the hydrological model. All initial states converge to the same projection curve after about 10 years.

Comparison of Raingauge Variability at Musoma & Bukoba Comparison of Raingauge Variability at Musoma & Bukoba Located on Opposite Sides LV Located on Opposite Sides LV

Requires Uncoupled ModelsRequires Uncoupled Models

Figure shows a surprising complete reversal in the observed decadal-scale rainfall oscillation at two locations on opposite shores of Lake Victoria. We believe that such a dramatic switch occurring over such a short distance O(200km) across Lake Victoria is in response to a common underlying regional climate anomaly regime. This is compelling testimony of the need for application of higher resolution regional climate models compared to GCMs which cannot resolve the salient characteristics of such an important source of livelihood, for water and hydroelectric power, for over 300 million inhabitants of LVB and the River Nile Basin.

Navigation Safety over Lake Victoria

A new East African Community Program

STRENGTHENING METEOROLOGICAL SERVICES ON LAKE VICTORIA TO ENHANCE SAFETY OF NAVIGATION

AND

EFFICIENT EXPLOITATION OF NATURAL RESOURCES

RegGCM3-POM simulation in December 1988 average over Lake Victoria. (a) 850mb wind at 6UT, and (b) lake surface temperature

Requires full hydrodynamics of Lake Victoria

Summary• Data resolution is a major problem. The 0.5 degree resolution seems to be the

minimum threshold acceptable for district scale assessment. Station data is not the solution at this time because the coverage over the semi-arid districts is very poor.

• Present climate data quality is acceptable for social-economic planning at district level & Inherent data uncertainties are a limiting factor and need to be reduced by improved monitoring of baseline climate

• Over the arid and semi-arid regions rain-gauge data coverage is very marginal & monitoring over these regions need to be upgraded

• Currently model-based climate information is available at regional scales & incompatible for broad range of end users

• Information about intraseasonal time scales is important for applications such as wildlife management, such onset & withdraw of the rains

• Require models that are not only high resolution but also support the physics of the critical mechanisms; require full hydrodynamics of Lake Victoria for a vriety of important applications such as, fisheries, pollution, hydroelectric power generation & marine navigation safety