Plz surf through these web pages..

http://www.ascleiden.nl/Pdf/infosheet2.pdf

http://nersp.nerdc.ufl.edu/~vecy/LitSurvey/Jury02_JAM.pdf

This paper analyzes the evolution of the West African Monsoon in the last 170 years. It is not for the whole continent but you might find it interesting:

http://onlinelibrary.wiley.com/doi/10.1002/qj.2601/abstract

Hi

Those papers deal with this topic. 

Another study is under review dealing with rainfall change or Africa for 1940-1999 but not yet available. I can send it to you when accepted.

Best

Gil

Article The rivers of Africa: Witness of climate change and human im...

Article Rainfall and river flow variability in Sub-Saharan Africa du...

Hi Alfred,

The post at the link below provides results and commentary on a study that assessed change in temperature variation that included Africa. The post cites the study PI but does not include a reference paper.

http://www.g-feed.com/2012/08/is-temperature-variance-changing.html

Thanks for a lot for the replies - I just wanted to update that I found some data in the work group report of the IPCC on managing the risks of climate extremes: https://wg1.ipcc.ch/srex/

IPCC (2012) Managing the risks of extreme events and disasters to advance climate change adaptation. In: A Special Report of Working Groups I and II of the Intergovernmental Panel on Climate Change (eds CB Field, V Barros, TF Stocker et al.), Cambridge University Press, Cambridge, NY, USA.

I also compiled a figure based on this report and on the IPCC report of 2014 summarizing global trends (attached), which might be informative.

Dear Colleague

Did you use our answers? Were they useful?

Thanks for your return if possible

Sincerely

Gil

There is an interesting new publication from CIGAR on this topic:

https://ccafs.cgiar.org/publications/rainfall-variability-and-drought-characteristics-two-agro-climatic-zones-assessment#.WsdhWpfA9PY

Thanks Gil for your past input!

Hi Alfred,

There are a couple of papers that have been done by a modeling group called CORDEX but these are mostly on projected (future) climate over sub regions (east, west, central, southern Africa) that have been posted by Alexandra Dosio. The literature may not answer your question but be of interest to you in terms of future scenarios and the CORDEX models have been found to be able to simulate the regional climate trends (post 1970s) well. Let me know if you need the papers sent to you- they are all open access though.

Hi

if still useful the paper about the creation of a new rainfall gridded data set for Africa at monthly time step January 1940 to December 1999, only from observed ground data.

Article A New 60-year 1940/1999 Monthly-Gridded Rainfall Data Set for Africa

and the data are here

Data HSM_SIEREM_AFRICA_40_99_V1b

Thanks Gil, looks interesting!

Hi Alfred

tell me if you had some use of this file or if you have any question about it.

We are also releasing free runoff data for African rivers here

https://www.researchgate.net/project/Gridded-data-sets-for-West-and-Central-Africa-Basins-discharges-contours-and-GIS-layers

together with several gridded data sets to use in GIS

Here is a website showing daily updated map of the world surface temperature anomaly.

You can see that the temperature anomaly between the tropics is particularly increasing since some years, and in Africa the rise is also very important since the start of the year.

I think it is very important to look at Africa not as a whole, but as different regions (Maghreb, Sahel, central East coast (Port Sudan to Mogadishu), Congo Basin, the zone between the Sahel and the Atlantic, the region around Lake Victoria (which has a huge stabilising impact on climate in the downwind surroundings), and one or more regions further south (I don't know much about the southern hemisphere unfortunately).

Then, it is important to identify the physical mechanisms underneath the variability (SST fluctuations such as AMO, ENSO, IOD; land use change, global climate change patterns, etc.). Once we understand the interaction between the explaining physical mechanisms of variability, we can analyse how these mechanisms are expected to change in the future (all at the same time!) and what their combined influence will be on temperature or precipitation or evapotranspiration or runoff coefficients etc. in the region of interest.

In addition to the above replies, Africa has been portrayed as the most vulnerable region to the impacts of global climate change because of its reliance on agriculture which is highly sensitive to weather and climate variables such as temperature, precipitation, and light and extreme events and low capacity for adaptation.

Read the articles attached herewith for better understanding.

thanks for the papers

Gil Mahe i have taken timeseries for rainfall in the Sahel, and calculated 11-year and 21-year moving SD. would that be a useful starting point? Interestingly, while the SD changes over time, if you plot it as percentage of 11-year (or 21-year) moving average rainfall it remains fairly stable. if i'm not mistaken, there was actually a slightly reducing trend in SD in recent years. What i found very interesting is that in the late 1940s the variability around Lake Chad peaked for a while, possibly related to the 1947 drought. Plotting rainfall anomalies for the region by year, 1947 has a different pattern. Normally droughts are either concentrated on the northern edge of the Sahel or on the Atlantic Coast (and into the continent around 5N). Occasionally, and on the looks of it correlated to weather patterns over the Ukraine, the area under drought is a triangle from the Atlantic Coast into the Sahel. So we may be dealing with different drought patterns to analyse. What is your take on this?

Timmo Gaasbeek you are right, the drought pattern seems different between the West and the East of Sahel, where the drought is much less visible in time series, and the South of Chad is in this area. In a study I found that some statistical test of change in time series did not found breaks at the turn of the 70s in this area, while it was recorded the major climatic rupture point elsewhere in West Africa.

In case you might be interested, the link toward the paper.

Article 1896–2006 Sahelian Annual Rainfall Variability and Runoff In...

Dear

I am sharing with you some work that addresses the issue in Senegal and in the Senegal River basin.

Best Regards

Can you confirm that the rainfall has durably changed in your country ?

Here is a study on the topic in the Senegal River Basin:

Article Long-term trend analysis in climate variables and agricultur...

The discharges variability is not only that of rainfall, due to complex interactions with surface and groundwater processes and human impacts.