Meteorological Instrumentation

Information Flow

Regional Offices

SAWS AWS Station Network

Rainfall data Network

Types of Stations Weather offices (SAWS regional offices) Automatic Weather Stations AWS Including Aviation AWSs – requiring minimal human intervention ARS Rainfall stations SST Climate stations(1st, 2nd and 3rd order stations)

Types of Measurements Manual and Automatic Temperature (°C) Humidity (%) Pressure (hPa) Rainfall (mm) Wind speed (knots or m/s) and Direction degrees Present Weather, Clouds, Visibility Sunshine Solar radiation

SAWS technicians can provide comprehensive remote support The main advantages: They are easy to maintain and do not need highly skilled technicians for basic maintenance. The sub-assemblies and sensors can be easily interchanged in the field. The sensors used are interchangeable across the networks and there is no need to modify the systems when changing the sensors. The software is internally developed and can be maintained by SAWS personnel. The algorithms used to derive meteorological variables are the same across the whole network and are documented. SAWS technicians can provide comprehensive remote support These systems are developed to withstand harsh African climate and weather. They require minimum maintenance and can be easily maintained by personnel with basic electronics knowledge. The system is in-house built and consist of locally accessible components, although the sensors and/or loggers are imported. The whole system is sited at the filed about 300m meters from the runway. It consists of the control unit, meteorological instrumentation and peripherals.

Measured parameters NO. PARAMETER UNIT SENSOR DESCRIPTION 1. Air Temperature Degrees Celsius (OC) VAISALA HMP 155 2. Relative Humidity Percentage (%) VAISALA HMP 155 3. Air Pressure hectoPascals (hPa) VAISALA PTB 110 4. Precipitation Millimetres (mm) HYDROLOGICAL SERVICES TB-3/0.2 5. Wind direction Degrees (O) RM YOUNG 05103 6. Wind Speed Meters per second (m/s) RM YOUNG 05103 7. Wind gusts Meters per second (m/s) RM YOUNG 05103 DEDUCED Parameters NO. PARAMETER UNIT 1. Dew point Temperature Degrees Celsius (OC) 2. Wet Bulb temperature Degrees Celsius (OC) 3. QNH hectoPascals (hPa) 4. QFE hectoPascals (hPa) 5. Pressure tendency and amount hectoPascals (hPa)

Control Unit Components 1. Mini solar charge controller (CMP12) for solely solar powered system; SAWS developed power supply or the of- the-shelf unit. 2. Campbell Scientific CR10X data logger with SAWS developed wiring panel or Campbell Scientific CR1000 Data Logger and wiring panel. 3. Amphenol or Panel MTG SKT 16A 24P and side entry plugs. 4. LPU board (lightning protection unit). 5. Radio links/wi-fi/Bluetooth to the local weather office and ATC tower computers. 6. GSM cell phone modem for communication to the SAWS APN network for aerodromes without the local weather office. 7. Pressure transducer. 8. Maintenance free Lead Crystal battery (12V 7.2Ah)

Power sources Primary and Secondary Power Battery  A 12Vdc/7.2Ah lead crystal battery is the primary power supply for solar powered units. This provides power to the logger.  A 12Vdc/7.2Ah lead acid battery is the primary power supply for mains powered units. This provides power to the logger. Mains Mains – 220VAC 60Hz plug is a secondary power and charges the battery. Solar panel Solar panel – This ~10 Amp/18Vdc panel is the secondary power and charges the battery. This solar panel charges the battery during the daytime and the battery supplies the power at night As a rule of thumb, solar output is at its optimum for only 5 hours each day. As such, mounting angle and position are vital Mini solar charge controller (CMP12) for Solar powered installations This unit is used when electricity supply to the system is solar powered only  5Vdc – is provided by the logger to sensors requiring 5Vdc

Temperature Graph

Rainfall Graph