Sample NMS Reference Report by YONTCHANG G - University of ...

C. METHODOLOGY:
The methods used to achieve the objectives mentioned above are the following:
All these results describe the rainfall data for Douala, Cameroon and were computed (plots,
graphs, tables, figures, risks or variability calculations) using Instat+ v3.36 and Excel
packages. To define the events of interest (start of the season, dry spell) the climatic>>Events
menu options from INSTAT were used. Then the sowing dates were extracted and analyzed
based on the below definitions.
1. Find the dates when sowing are possible using the suitable definitions:
a)- First date from 1 st March getting more than 40mm in 1,2,3 or 4 days;
b)- First date from 1 st April getting more than 40mm in 1,2 or 3 days;
c) – First date from 1 st May getting more than 40mm in 1 or 2 days;
d) – First date from 1 st June getting more than 40mm in 1 day
2. Assessment of the risk of flooding with crop failure
e) – Fist occasion after 1 st August with more than 100mm totalled over 2 consecutive days
and no dry spell of 3 days or more in the next 30 days. If the event was observed at least once
we define that a year experiences a flood in low-land areas.
f) – First occasion after 1 st August with more than 100mm totalled exactly over one day. If
the event was observed at least once we define that a year experiences a general flood with
crop failure.
g) – The average rainfall total for August will be compared with the average totals for the
other months to get a general idea as to how wet the month is.
Then the month will then be broken down in 4 weeks as specified above, where the average
total for each week will be looked at and the highest rainfall totals will be highlighted.
After this, a count of the number of days with at least 100mm in exactly 1 day will be looked
at for each week, then find the average number of times per week each of these occurred over
the past 57 years. This will give the probability of the event of flooding, and therefore the
level of risk for encountering crop failure in either week 1, 2, 3 or 4 will be estimated.
3. Boxplots for visual comparison, descriptive statistics as dates and Comment
on the summaries.
4. Some conclusions for the client (Ministry of agriculture) based on these
summaries and risks calculations.
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