Developing Crop Calendar for Global Climate Change Using GFDL CM 2.1 to Eastern Amhara, Ethiopia

Abstract

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.