Operator`s manual

Manual

1.1 General

This manual presents detailed instructions for the installation, operation, and maintenance of the Automatic

Weather Stations (AWS) installed on buoys in Lake Nasser in Egypt by the FAO Nile Basin Water Resources Project.

The monitoring equipment was procured from Campbell Scientific, USA. This company has a proven track record in

Africa, and a number of Campbell Scientific AWS have been operational in the basin for several years.

The reader is advised to study this manual carefully before starting to work with the monitoring equipment. The

project experts have worked hard to present the user instructions as concise as possible with no compromise on the

necessary details. Background information on the functioning of the various instruments is presented at appropriate

occasions. It is hoped that this information will provide the user with a clear overview of the role of each AWS

element in the data acquisition process.

In the remainder of this text, Automatic Meteorological Station is referred to as Met Station.

Main purpose of the Met Stations installed on buys is to collect continuous high quality climatological data for the

quantitative estimation of open surface water evaporation from Lake Nasser. Such information is also used for other

purposes, including:

- Climate change assessment;

- Hydrological analysis;

- Agricultural planning, etc.

The Met Stations are equipped with sensors for (1) solar radiation, (2) air temperature at 2 meter and 4 meter

heights, (3) relative humidity at 2 meter and 4 meter heights, (4) wind speed at 2 meter and 4 meter heights, (5) wind

direction at 2 meter and 4 meter height, (6) water temperature at the surface of water and 20 meters inside water.

Due to the buoy pitch and roll character, the station also include a digital compass sensor for correcting the wind

direction. These parameters facilitate estimating potential (open water) evaporation using the Harbeck, Penman-

Monteith or Priestley-Taylor approach.

The project has advocated the introduction of electronic monitoring equipment in the Nile basin. The use of

electronic sensors connected to a datalogger is now well established in the world, and carries many advantages.

For example, it facilitates automation of data processing. It is the experience of the authors that processing of the

observations often forms the main obstacle in the data collection process, not so much the actual measurement.

Another major benefit of electronic monitoring is the acquisition of a continuous set of sub daily data values. This

provides important additional information on the behavior of the often highly variable climatological parameters.

The project operated an AWS at its compound for testing and manual preparation purposes for several months.

This station worked impeccable and did not show any technical problem in the testing period. Based on this

experience, and the fact that other Campbell Scientific AWS’ are satisfactorily operational in the basin for several

years now, the project believes that automatic monitoring of meteorological parameters is feasible within the Nile

basin. However, this under the provision that the user follows the operation and maintenance instructions presented

in this manual.

1.2 Individual Components of the Met Station

Figure 1 shows a sketch of the Automatic Meteorological Station specifically tailored and sensor selected for the

environmental conditions in Lake Nasser in the Nile basin. Obviously, this figure only shows the external hardware

components. A number of essential elements (datalogger and power supply) are placed within the instrument

container and therefore not visible on this picture.

Introduction