cc: m.hulme@uea.ac.uk date: Wed, 16 Sep 1998 15:02:55 +0100 from: Dave Slade subject: RE: CONFIDENTIAL REFEREE FEEDBACK FOR STANDARD GRANT GR3/11950 to: nwal@soton.ac.uk Dear Dr Arnell, This e-mail contains comments provided by the referees of your standard grant (grant number in subject line) which you may wish to respond to. Please note that you are only being sent those parts of the report that contain queries or criticisms of your proposal and these may not reflect the overall tone of the report or the funding recommendation. Should you wish to respond to the points raised by the referees, please do so by the end of 29th September 1998 to allow us to include your response in the papers sent to the committee reviewing your grant. We realise that this is a short period of time and would encourage you to submit your response by e-mail or fax where possible. Please make sure that you include your grant number. Where appropriate (and possible) this e-mail has been copied to the other PI's on the grant in case the lead PI is out of contact. However we can only accept one response to these comments (preferably from the lead PI) - not one from each PI contacted. Please note that further referee comments that have arrived late may be forwarded to you as they come in. Please acknowledge receipt of this e-mail. Yours sincerely Dave Slade ----------------------------------------------------------------------------------------- REFEREE C The proposal seeks to simulate time series of monthly streamflow using regional climatic time series or patterns of rainfall, temperature and other data that can be given to the hydrological model which in turn are calculated to be correlated to large scale atmospheric or oceanic indices. The latter might be the North Atlantic Oscillation, El Nino or spatial patterns of sea surface temperature or atmospheric variability. The way this is to be done is described very little. In fact some fairly concrete examples of possible approaches to one or two specific problems could have been given. I have a feeling that the hydrological modelling part of this proposal has been thought out more than the climatic inputs. There has been much work relating ENSO to rainfall deficiency or excess over the globe, and also to temperature anomalies. Presumably this work (key papers might have been referenced) can be readily adapted to calculate large scale streamflow using the CRU climatic data sets and the large scale model. The links between NAO and rainfall and temperature in the winter half year have also been investigated by several authors and are very strong in some parts of Europe and perhaps North West Africa. Evidence is also starting to emerge from UKMO research that the winter NAO might have a predictable component and that decadal modulation of the interannual variability is important. In addition there is evidence of strong non-ENSO influences of sea surface temperature patterns (e.g. in the Atlantic) on some South American and African rainfall, and presumably streamflow. Note that work is going on in Australia and South Africa, with links to the UKMO, on this problem. This background favours the proposal. The proposal does not note that a complicating factor in ENSO-related rainfall predictability is the time-varying nature of some of the links. An example is Australia where this problem has long been known, if so far largely ignored in, for instance, the Bureau of Meteorology RAINMAN service to farmers and hydrologists. Recent research seems to implicate decadal to multidecadal modulation of sea surface temperatures in the Pacific. One might suspect this problem is important in Southern Africa where large quasi-bidecadal variations of rainfall are well known. In both cases active research is now being done to investigate decadal modulation of interannual rainfall teleconnections. The misbehaviour of some 1997-8 El Nino teleconnections might be related in part to this. Decadal/multidecadal modulation of interannual variability is starting to emerge more generally as an important paradigm, stimulated by recent published evidence for mechanisms in the Pacific and the Atlantic. Since the proposal involves hydrological simulations over the whole twentieth century, this aspect of the problem should be explicitly considered. The proposal needs to be revised to demonstrate in more detail that a strong start can be made in two or three key large regions (including Europe perhaps), using current or emerging knowledge about climatic teleconnections. It would help to reformulate the project to consult with other selected projects that have related aims, and do a better review of teleconnection and climate mechanisms literature. REFEREE E The overall goal of the proposal is to test the hypothesis that there is an influence of large scale phenomena (such as ENSO) in hydrological records. This is a laudable and meritorious goal and one that should be addressed. However, the test should be made using real hydrological records not with synthetic hydrological records created by introducing a synthetic daily pattern into monthly precipitation records and then calculating synthetic runoff records. The daily pattern of precipitation may itself depend on the global phenomenon and there will always be argument about the realism of the hydrological model (despite the intention to test it against data). The net effect of introducing this artificiality will be to denigrate rather than enhance the credibility of any relationship found. The fact that the actual hydrological records may not be globally available or may be unreliable in certain parts of the world (if this is in fact what motivates suggesting the approach described in the proposal) does not justify replacing true records with artificial records to carry out the test. Rather, the testing should be restricted to regions where the data is robust enough to allow it. ::::::::::::::::::::::::::::::::::::::::::::::::::: Mr Dave Slade Awards & Training NERC Tel: 01793 411783 Fax: 01793 411655 e-mail:david.a.slade@nerc.ac.uk