Meteorological Station Siting Must Satisfy Three Fundamental Requirements Representativeness, Accuracy, and Comparability

The selection of a site for a meteorological station must satisfy three fundamental requirements: representativeness, accuracy, and comparability. The station site should be situated in an open, flat area, avoiding valleys and depressions. The distance between the observation field and any isolated obstruction must be at least three times the height of the obstruction; for large-scale obstructions, this distance must exceed ten times their height. Furthermore, no tall-stalked crops may be planted within a 10-meter radius of the site.

The siting of a meteorological station directly determines the quality of the meteorological data generated. According to the *Technical Requirements for Siting National Meteorological Observation Stations* (QX/T 684-2023) and the *Technical Requirements for Siting National Basic Meteorological Stations* (QX/T 685-2023)—both issued by the China Meteorological Administration—meteorological station siting must fulfill three core requirements: representativeness, accuracy, and comparability. Representativeness implies that the observed data accurately reflect the weather and climate characteristics of the majority of the surrounding region; accuracy implies that the observational records truthfully reflect actual meteorological conditions; and comparability implies that data collected from different stations can be effectively compared.

Regarding geographical location, a meteorological station should be constructed at a site that is representative of the surrounding region's climatic characteristics. It should ideally be situated upwind of the prevailing local wind direction, while avoiding topographical features such as valleys, depressions, steep slopes, and sheer cliffs. The observation field is required to be flat and open on all sides, free from nearby interference sources such as tall buildings, industrial or mining facilities, and smokestacks. A 1,000-meter radius surrounding the observation field is designated as a "detection environment protection and control zone"; within this zone, the ratio of any building's height to its distance from the observation field must be less than 1:10, and the minimum distance between any obstruction and the observation field's perimeter fence must be no less than 50 meters. Furthermore, the obstruction elevation angle in the directions of sunrise and sunset (based on the local azimuths for sunrise and sunset) must not exceed 5 degrees.

Regarding the control of environmental conditions, a meteorological station should be situated at a safe distance from various potential sources of interference. The minimum distance between the observation field's perimeter fence and a railway embankment must exceed 200 meters; the minimum distance from a highway embankment must exceed 50 meters; the minimum distance from any artificially constructed body of water must exceed 100 meters; and the minimum distance from interference sources such as landfills or sewage outlets must exceed 500 meters. No tall-growing crops may be planted within a 10-meter radius surrounding the observation field, in order to ensure unimpeded airflow. The perimeter of the observation field should be enclosed by a sparse fence approximately 1.2 meters in height; the field itself must maintain a uniform grass cover, with the grass height not exceeding 20 centimeters.

Regarding equipment layout, a surface meteorological observation field should be oriented along north-south and east-west axes, with a standard dimension of 25 meters by 25 meters. The installation of instruments within the field adheres to the following principles: "maintain adequate spacing to prevent mutual interference; arrange from north to south in descending order of height, and align in rows from east to west; and position instruments near pathways to facilitate observation." The north-south spacing between instruments must be no less than 3 meters, the east-west spacing no less than 4 meters, and the distance from any instrument to the perimeter fence no less than 3 meters. The station building housing the meteorological facilities is typically constructed to the north of the observation field. Once established, a meteorological station should maintain long-term stability and should not be relocated without compelling reason, so as to preserve the continuity of the observational data.