Developing Crop Calendar for  Global Climate Change Using GFDL  CM 2.1  to  Eastern Amhara, Ethiopia
Creators: name: Gashaw Bimrew Tarekegn
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2009

description: Nowadays  the  issue  of climate  change  has  become  a substantial  subject  matter  over  which  many 
researches  are  conducted  intensive  studies.  Moreover,  the  effect  of climate  change  has  imposed  a 
negative  externality  in  different  parts  of  our  planet  being  practically  manifested  by  different 
magnitudes  of  human  and  resource  loses .  Nevertheless,  the  day  to  day  life  of  society  is 
significantly  affected  by  climate  variability  and  extremes  rather  than  climate  change. 
Accordingly,  Ethiopia  in  general  and  Amhara  Regional  State  in  particular  has  been  affected  by 
these  climate  variability  and  extremes.  In  particular,  the  Eastern  Amhara  sub  region  is  affected 
by  recurrent  meteorological  drought.  Despite  the  fact  that  agriculture  is  the  livelihood  of the  sub 
region,  it  is  mostly  weather  sensitive  as  most  of  agricultural  practices  are  rainfall-dependent. 
However,  the  communication  of  'tailored'  climate  predictive  information  for  flexible  and 
improved  decision  making by  the  farmers  in  the  risk management is  minimal. 
Out  of  IO  I  stations  34  stations  are  selected  based  on  the  availability,  continuity  and  quality  of 
data  and  representing  the  climatic  characteristics  of the  study  area.  Major  and  cash  crops  of the 
study  area  were  collected  from  Debre  Birhan  ans  Sirinka  Agricultural  Research  Institutes. 
Thieson  polygon  method which  takes  into  account topography  effect  of the  study  area  and  more 
superior  and  more  reliable  than  other  methods  is  used  to  filling  missing data  and  categorize  the 
selected  station  under the  three  grid  points  in  the  study  area  ..  The  consistency of rainfall  record  is 
tested  by  double-mass  curve  method.  The  model-  GFDL  CM2.1  used  to  extract  data  for  the 
prediction  for  different  climate  variables  accessible  on  in  the  internet  is  one  of the  latest  update 
model  developed  from  CGCM  .  Validation  and  evaluation  of  the  model  is  tested  using 
coefficient  of  determination  and  ANOV  A  test  and  for  the  LGP  the  onset  and  offset  date  more 
specifically  are  determined  from  the  total  monthly moisture  con  tent  by  interpolating  to  the  daily 
time  frame. 
Under  IPCC  climate  change  scenario,  the  GFDL  CM2. l  output  indicates  that  temperature  is 
likely to  increase  while rainfall  is  tending  to  decrease  in  the  21s t  Century.  In  general,  the  mean air 
tem perature  will  i ncrease  by  !.7°C,  3.0°C  and  3.6°C;  l.6°C,  3 . 1°C  and  3.1°C  and  l.6°C,  3.3°C 
Vlll 
and  4 . 3°C,  while  annual  rainfall  will  be  decreased  by  1  %,  3%  and  1  %;  4%,  8%,  12%  and 
13%,24 . 4%  and  30 . 8% by  2020s,2050s and  2080s over  SEA,CEA and NEA  respectively. 
Variability and  extremes  analyses  are  made  over  the  sub  region  provides  increase  of  temperature 
and  decrease of  precipitation  for  the  projected years  2009-203  8 using mean monthly Tmax, Tmin 
and  Pcpn  at  all  sub  regions  of  Eastern  Amhara.  On  the  other  hand,  the  model  simulation  for  the 
two  major seasons  bclg and  kirmct  mainly manifests-complete  failure by  90%  and  83.3% in  belg 
season  over NEA  and  CEA,  respectively.  Whereas 53 . 33%  is  projected  that  belg rainfall  is  more 
likely to  be  sufficient  for  corp  production over SEA.  And  model simulation  result  indicates  NEA 
wi  11  receive  less  than  600mm  kirmet  rainfall  from  the  year  20  l  O  to  2033  where  as  CEA  is 
expected  to  receive  greater  than  800mm  except  for  the  years  2013, 2020  and  2034.  In  contrast, 
SEA  is  likely to  receive  sufficient amount of  rainfall  except  in  the  year 2034.  In  the  year  2034  all 
areas  of  eastern  Amhara region  will encounter deficient rains  in  kiremt. 
Analysis  of  total  soil  moisture content  of the  model  output  has.  been  used  to  determine  the  onset, 
offset  and  length  of  growing  period  of each  sub  region  under  study.  The  results  revealed  that 
NEA  will  possibly  have  three  years  with  no  growing  season  and  18  years  with  late  onset  and 
early  offset  of the  growing  season.  That  is;  the  length  of growing  period  will  be  less  than  three 
months;  9  years  will  have  3-6  months  of growing  season.  Thus  it  will  be  highly  recommended 
that  as  per  the  simulated  LGP  shows  both  short  and  long  cycle  crops  are  likely  to  be  productive 
over  CEA  and  SEA.  On  average  .  late  May  to.  early  June  and  early  to  late  November  are  the 
starting  and  ending  dates  of  cropping  calendar  over  SEA  and  mid  Jun  to  early  July  and  mid 
November  to  early  October  are  the  starting  and  ending  dates  of.cropping  calendar  over  SEA. 
NEA  has  three  years  starting  date  on  August  and  ending  date  from  early  November  to  mid  of 
December  and  for  the  rest  of  the  three  years  the  situation  is  expected  to  be  favorable  f or  the 
modest  growing  seasons  years.  During  the  years  2027, . 2033  and  2037  the  starting  and  endi ng 
dates  arc  projected  to  be  in  Jun-10,_ July:.10, .  Sept-IO  and  Decembe r - IS ,  Nov- IO  December-15 
r espectively.