FFZ-01Z Digital Water Surface Evaporation Station

1. Overview

The FFZ-01Z digital water surface evaporation station is manufactured in accordance with the relevant requirements of the "Water Surface Evaporation Observation Specification" SD265-88 of the Ministry of Water Resources and Electric Power of the People's Republic of China and the "Ground Meteorological Observation Specification" of the China Meteorological Administration in 2003, and is used for automatic observation of water surface evaporation processes.
The definition of "digital water surface evaporation station" refers to a water surface evaporation observation station where the evaporation meter, rain gauge, overflow bucket, data acquisition and control process, and water replenishment process that make up the evaporation station are all digitized.
The resolution of the evaporation meter and rain gauge of the FFZ-01Z evaporation station is 0.1mm, and the overflow resolution is 0.025mm, which meets the highest level requirements of relevant national standards. The table format of precipitation and evaporation data meets the requirements of data storage and compilation, and can be used to equip various types of water surface evaporation observation stations, replacing tedious and complex manual observation and achieving automatic observation and recording of water surface evaporation.
The FFZ-01Z evaporation station can be connected to a GPRS data transmission device to form a telemetry station.
The equipment on this site is limited to use during non freezing periods.
The evaporation meter, rain gauge, overflow bucket and other devices in the equipment on this site should be regularly maintained according to the requirements of the relevant product manual.
2. Working principle
This evaporation station system uses evaporation meters, rain gauges, and overflow buckets as basic observation tools. The collector automatically collects, processes, and displays information on evaporation, precipitation, and overflow processes, and automatically controls the evaporation bucket, overflow bucket replenishment, and drainage processes. The collector is connected to the upper computer system and the data transmission communication unit (RTU) through RS485/232 communication interfaces. With the application software provided by the system, remote monitoring of water surface evaporation process information and data compilation and storage can be achieved.
The water level height of the evaporation tank in the operating evaporation station should be maintained at the water level mark line. On days without precipitation, the collector automatically collects changes in the water surface height inside the evaporation bucket to calculate the evaporation rate. Whenever the water level in the evaporation bucket drops to the agreed value (10mm below the water level mark line), the collector controls the water replenishment pump B3 to work at the observation day boundary time (8:00 on hydrological boundary day and 20:00 on meteorological boundary day), automatically replenishing water to the evaporation bucket and water ring, so that the water level in the bucket returns to the height of the water level mark line. Then, using the height after replenishment as the starting point, the evaporation rate of the next period is measured.
On rainy days, when the water level in the evaporation bucket rises to the agreed value (10 mm above the water level mark line), the collector drives the overflow pump B1 to work, causing water from the evaporation bucket to flow into the overflow bucket. When the water level in the overflow bucket reaches the agreed value, the overflow process ends. After collecting and calculating the overflow flow data, the collector starts the overflow bucket drainage pump B2 to work, and discharges the water in the overflow bucket to the agreed bottom water height.
According to the "Water Surface Evaporation Observation Specification" and the "Ground Meteorological Observation Specification" of the National Meteorological Administration, the calculation formula for evaporation is:
Evaporation rate=(measured value of evaporation tank water level - calculated value of evaporation tank water level)+precipitation - overflow rate
The above equation can be simplified as: QF=(Wt-W0)+Qj Qy
In the formula: QF: represents the water surface evaporation rate, unit: mm
Wt: represents the water level of the evaporator tank at the measurement time (t), unit: mm
W0: represents the water level of the evaporation tank at the starting time, unit: mm
The Wt and W0 values are automatically measured by the FFZ-01 digital water surface evaporation meter.
Qj: represents the precipitation during the measured period. The Qj value is provided by the JFZ-01 digital rain gauge, in millimeters
Qy: represents the overflow volume during the measured period, and the Qy value is automatically measured by the overflow bucket, in millimeters