Classical barometer
- No record of pressure changes
- Useless for weather observation – unless the user is prepared to read and record the atmospheric pressure manually every 15 minutes!
- No storm warning
Drum barographs
Drum barograph has much larger physical dimensions.
Size – a drum barograph takes up between 10 and 15 times the volume of the Meteograf
Weight – a drum barograph weighs between four and eight times as much as the Meteograf
The paper has to be changed every week
Ink has to be refilled and the pens have to be changed regularly
The recording mechanism is subject to wear, and abrupt motions of the ship (for example, in heavy seas) can affect the recording
The drum mechanism means that the pressure record of pressure variation is often printed on a curved, rather than a linear axis – which makes quick and accurate interpretation of the data difficult
No digital record
No additional functions such as Storm Alarm, Magnification, Transport, Time Zone Change, etc
Difficult adjustment / compensation
Cannot adapt easily to changes in altitude, for example during transport. Some devices can even be damaged by a change in altitude!
Laptop barograph
- Laptop required
- Display only visible if the laptop is running
- Dependent on external electrical power; either the vessel's power supply or the PC's battery. If this fails (or the PC's batteries run flat,) all functions are lost
- High power consumption – typically 30mA at 12 V, approx. 27 Ah in a month
- Cannot be left running when the vessel is unmanned for more than a short period.
Baroscope
- No permanent data record
- Display shows only previous one or two days' recordings. Gradual pressure fluctuations are thereby impossible to detect
- High power consumption – typically 30mA at 12 V, approx. 27 Ah in a month
- Dependent on external electrical power; if this fails, all functions are lost
- Cannot be left running when the vessel is unmanned for more than a short period
- Displays averaged pressure curve – current ambient pressure is not immediately readable
- Storm warning unresponsive, as only pressure fluctuations over a period of an hour are considered. The Meteograf storm warning has a minimum resolution of only 15 minutes
Domestic "barographs"
- A proper comparison is not possible, as these instruments generally have very limited accuracy and resolution. In addition, the temperature error is so great as to make the devices worthless for serious weather observation. (Refer to trade literature.)
