CIRCULAR

Technical regulations on monitoring and providing meteorological and hydrological information and data for specialized meteorological and hydrological stations

meteorological and hydrological services for dedicated meteorological and hydrological stations

Pursuant to the Meteorological and Hydrological Law 2015;

WHEREAS, Decree No. 38/2016/NĐ-CP dated May 15, 2016 of the Government detailing certain provisions of the Law on Meteorology and Hydrology;

On the basis of Decision No. 36/2017/NĐ-CP dated April 4, 2017, of the Government stipulating the functions, tasks, powers, and organizational structure of the Ministry of Natural Resources and Environment;

At the proposal of the Director General of the National Centre for Hydro-meteorological Forecasting, the Head of the Science and Technology Department and the Head of the Legal Department;

The Minister of Natural Resources and Environment issues this Circular stipulating technical regulations on monitoring and providing meteorological and hydrological information and data for specialized meteorological and hydrological stations.

PART I

GENERAL PROVISIONS

Article 1. Scope of Regulation

This Circular stipulates technical regulations on monitoring and providing meteorological and hydrological information and data for specialized meteorological and hydrological stations.

Article 2. Applicability

This Circular applies to agencies, organizations, and individuals related to the monitoring and provision of specialized meteorological and hydrological information and data.

Article 3. Explanation of Terms

In this Circular, the following terms are understood as follows:

1. A specialized meteorological and hydrological station is a location selected according to specific technical requirements to conduct meteorological and hydrological monitoring for specific purposes established, managed, and operated by ministries, ministerial-level agencies, government-affiliated agencies, provincial people's committees under central cities (hereinafter referred to as ministries, sectors, localities), organizations, and individuals, including surface meteorological stations, agricultural meteorological stations, upper-air meteorological stations, weather radar stations, hydrological stations, marine stations, rain gauges, and other specialized stations.

2. The monitoring location for meteorological and hydrological observations is where facilities are installed, measurement instruments are set up, and meteorological and hydrological monitoring is conducted.

3. Meteorological and hydrological observation facilities are material bases that meet technical requirements for installing meteorological and hydrological measurement instruments and transmitting monitoring information and data.

4. Manual monitoring method is the activity of directly measuring and recording the value of elements on measurement instruments by humans.

5. Automatic monitoring method is the activity of measuring and recording the value of elements using automatic measurement instruments and transmitting them to users as needed.

6. Metadata is information describing data including content, format, quality, source, conditions, and other characteristics to guide access methods, managing authorities, access addresses, storage locations, and data preservation.

7. Data structure is the organization of numerical data reflecting hierarchical and interrelated groups of data.

8. Information type of data is the name, value type, and field length of information.

9. Measurement instrument or device is the technical means for conducting measurements.

Chapter II

TECHNICAL REGULATIONS

Section 1

SPECIALIZED METEOROLOGICAL AND HYDROLOGICAL MONITORING

Article 4. Elements of specialized meteorological and hydrological monitoring

Based on legal provisions or needs, purposes of using information and data, ministries, sectors, localities, organizations, and individuals select elements of meteorological and hydrological monitoring for each type of specialized meteorological and hydrological station, specifically:

1. Elements monitored at surface meteorological stations:

a) Radiation;

b) Atmospheric pressure;

c) Surface wind;

d) Evaporation;

đ) Air temperature;

e) Soil temperature;

g) Air humidity;

h) Rainfall;

i) Visibility;

k) Sunshine duration;

l) Cloud cover.

2. Elements monitored at agricultural meteorological stations:

a) Meteorological elements as specified in Clause 1 of this Article;

b) Soil temperature at deep soil layers and surface water temperature in rice fields;

c) Soil moisture at depths of 5cm, 10cm, 20cm, 30cm, 40cm, 50cm, 60cm, 70cm, 80cm, 90cm, and 100cm;

d) Wind at heights from 2m to 10m;

đ) Air temperature within crop communities;

e) Air humidity within crop communities.

3. Elements monitored at upper-air meteorological stations:

a) Radio-sounding station: atmospheric pressure; air temperature; air humidity; wind direction and speed;

b) Wind-measuring station (pilot or pilotsonde): wind direction and speed.

4. Elements monitored at weather radar stations:

a) Radar return field;

b) Centrifugal wind field.

5. Elements monitored at hydrological stations:

a) Water level;

b) Rainfall;

c) Water temperature;

d) Ancillary elements: flow direction, wind, waves, riverbed changes;

đ) Water discharge;

e) Suspended sediment discharge.

6. Elements monitored at marine stations:

a) Sea surface wind;

b) Sea visibility;

c) Sea level;

d) Sea waves;

đ) Sea surface condition;

e) Sea water temperature;

g) Sea water salinity;

h) Sea brightness;

i) Ocean currents.

7. Other specialized meteorological and hydrological monitoring elements based on needs and purposes.

Article 5. Density of Special Meteorological and Hydrological Stations

1. Based on requirements and purposes for using meteorological and hydrological information and data, ministries, sectors, localities, organizations, and individuals decide on the density of special meteorological and hydrological stations.

2. The density of special meteorological and hydrological stations in certain specific cases is as follows:

a) The distance between rain measurement stations ranges from 10km to 15km for one of the following areas: hills and mountains; windward slopes; annual average total rainfall over many years of 1,600mm or more; urban areas of type III or higher;

b) The distance between rain measurement stations ranges from 15km to 20km for midland and delta regions;

c) For calculating water inflow to reservoirs: in river basins supplying water to reservoirs with a total capacity of 500,000m³ or more, a rain measurement station should be arranged every 10km to 15km; in tributaries flowing into reservoirs with a basin area of 100km² or more, a flow measurement station should be arranged.³ if the distance exceeds this, arrange for a rain gauge station every 10km to 15km; in branches of rivers and streams flowing into reservoirs with a watershed area of 100km² or more, arrange for a flow measurement observation station;²at the point of releasing unmanned aerial vehicles;

d) Monitoring in national parks: each national park must have at least one meteorological station; additional meteorological stations may be arranged according to the scale of the national park's area but ensuring that the distance between stations is from 25km to 30km.

Article 6. Location of Special Meteorological and Hydrological Stations

1. Surface meteorological and agricultural meteorological stations:

a) Must be unobstructed, not blocked by objects;

b) Representing the monitored area, monitoring results are objective and accurate.

2. Upper-air and weather radar stations:

a) Must be unobstructed, not blocked by objects;

b) There should be no obstacles facing more than 60 degrees at the point where the balloon is released;⁰ meteorological and hydrological dedicated use

c) Radar scan beams are not blocked by terrain; there should be no obstructions appearing in large scanning angles above the horizon.

3. Hydrological stations:

a) Water level monitoring location: ensuring representativeness for the monitored area; able to monitor water levels from the lowest to the highest;

b) Flow and suspended load monitoring location: minimizing the impact of waves, wind, eddies, debris flow, and floating objects; the riverbed has few or no obstructions; stable riverbanks, simple cross-sections, without overflow beaches, controlling the volume of water in the basin.

4. Marine stations:

a) Wind monitoring location must be unobstructed, not blocked by objects, ensuring the characteristics of wind factors in the monitored area;

b) Water level and wave monitoring location must ensure representativeness for the monitored area, open towards the sea, able to monitor water levels from the lowest to the highest.

Article 7. Construction of Special Meteorological and Hydrological Monitoring Facilities

1. Types of monitoring facilities:

a) Surface meteorological and agricultural meteorological monitoring facilities: observation gardens for installing monitoring equipment, towers (poles) for installing automatic measuring devices;

b) Upper-air meteorological monitoring facilities: gas house, pump balloon area, surface observation garden for installing surface monitoring equipment and releasing balloons;

c) Weather radar monitoring facilities: antenna tower;

d) Hydrological monitoring facilities: elevation markers; water level monitoring facilities (benchmark staff, water gauge, self-recording well, installation of automatic measuring equipment); river flow monitoring facilities (main cable, current meter chain, position determination device, installation of automatic measuring equipment);

e) Marine monitoring facilities: elevation markers; water level monitoring facilities (benchmark staff, water gauge, self-recording well, installation of automatic measuring equipment); wave monitoring facilities; current monitoring facilities.

2. Technical requirements for installation and maintenance of monitoring facilities:

a) Facilities must be stable and secure; safe and convenient for equipment installation, operation, and maintenance; facilities must be maintained at least once a year, ensuring safety and quality of monitoring data;

b) Technical specifications for monitoring facilities are stipulated in Appendix 1 issued together with this Circular.

Article 8. Meteorological and Hydrological Measurement Instruments

1. Depending on the purpose and requirements for use, technical specifications of specialized meteorological and hydrological measurement instruments may be selected according to Appendix 2 issued together with this Circular.

2. Technical requirements for installing surface meteorological factor measurement instruments:

a) The installation location of surface meteorological factor measurement instruments shall be arranged within the observation garden specified in Section I of Appendix 1 issued together with this Circular;

b) Wind measurement instruments shall be installed at a height of from 10m to 12m above ground level, ensuring good ventilation, and the north direction of the instrument must align accurately with true north;

c) Temperature and humidity measurement instruments shall be installed at a height of 1.5m above ground level or floor, ensuring good ventilation and avoiding direct sunlight;

d) Rainfall measurement instruments with rainwater collection mouths shall be installed at a height of 1.5m or more above ground level or floor, ensuring good ventilation and being level;

đ) Sunshine duration and solar radiation measurement instruments shall be installed at a height of 1.5m or more above ground level or floor, not shaded by anything, the sensor axis must be aligned accurately with true north-south direction, ensuring levelness and correct latitude;

e) Evaporation measurement instruments shall be installed at a height of 0.27m above ground level, the measuring device surface must be level, ensuring good ventilation;

g) Atmospheric pressure measurement instruments shall be installed at a height of 1.5m or more above ground level, not exposed to rain or direct sunlight; the installation position of atmospheric pressure measuring devices must be referenced to national elevation;

h) Soil temperature measurement instruments shall be placed on the ground surface and deeper soil layers as required for observation, ensuring good ventilation and not shaded by direct sunlight;

3. Technical requirements for installing agricultural meteorological factor measurement instruments shall be implemented according to the provisions of Clause 2 of this Article, except that wind measurement instruments shall be installed at a height of from 2m to 10m, ensuring good ventilation, and the north direction of the instrument must align accurately with true north;

4. Technical requirements for installing upper-air meteorological factor measurement instruments shall be implemented according to the provisions of Points b, c, and g of Clause 2 of this Article;

5. Technical requirements for installing automatic water level measurement instruments:

a) Non-contact water level measurement instruments shall be installed fixedly at a position higher than the highest water level previously observed by at least 1.0m;

b) Contact water level measurement instruments shall be installed fixedly at a position lower than the lowest water level previously observed by at least 0.2m;

c) Non-contact flow measurement instruments shall be installed securely at a position higher than the highest water level previously observed by at least 1.0m;

d) Contact flow measurement instruments shall be installed securely, ensuring the ability to measure the best cross-sectional flow of the river;

6. Technical requirements for installing automatic marine factor measurement instruments:

a) Non-contact wave measurement instruments shall be installed fixedly at a position higher than the highest water level previously observed by at least 5.0m;

b) Contact wave measurement instruments shall be installed fixedly at a minimum depth of 5.0m during low tide;

c) Non-contact water level measurement instruments shall be installed fixedly at a position higher than the highest water level previously observed by at least 5.0m;

d) Contact water level measurement instruments shall be installed fixedly at a position lower than the lowest water level previously observed by at least 1.0m;

đ) Surface sea wind measurement instruments shall be installed at a height of from 10m to 12m, ensuring good ventilation, and the north direction of the measuring device must align accurately with true north;

7. Calibration and verification of meteorological and hydrological measurement instruments shall be carried out in accordance with the provisions of Article 19 of the Law on Meteorology and Hydrology.

Article 9. Frequency and methods of meteorological and hydrological observation

1. Frequency of observation:

a) For works subject to meteorological and hydrological observation as prescribed in Clause 3, Article 13 of the Law on Meteorology and Hydrology, they shall be carried out in accordance with Clause 1, Article 4 of Decree No. 38/2016/NĐ-CP dated May 15, 2016 of the Government detailing some provisions of the Law on Meteorology and Hydrology (hereinafter referred to as Decree No. 38/2016/NĐ-CP);

b) For other specialized meteorological and hydrological works, ministries, sectors, localities, organizations, and individuals shall determine the frequency of observation based on needs and purposes.

2. Methods of specialized meteorological and hydrological observation shall be implemented in accordance with the provisions set forth in Appendix 3 attached to this Circular.

Section 2

INFORMATION AND DATA PROVIDER METEOROLOGICAL AND HYDROLOGICAL SPECIALIZED OBSERVATION

METEOROLOGICAL AND HYDROLOGICAL SERVICES FOR DEDICATED USE

Article 10. Content and responsibility for providing information and data

1. Information and data provided include metadata and data of observed elements of specialized meteorological and hydrological observations.

2. The owners of works specified in point a, Clause 1, Article 9 of this Circular and the owners of other specialized meteorological and hydrological works shall provide meteorological and hydrological observation information and data in accordance with Clauses 2 and 3, Article 5 of Decree No. 38/2016/NĐ-CP.

3. Responsibilities for providing information and data:

a) Establish a list and quantity of information and data to be provided;

b) Ensure the safety and security of information and data before provision;

c) Provide initial metadata and promptly notify the information and data receiving agency of any changes in information;

d) Provide data to the information and data receiving agency in the correct structure and format;

e) During the process of providing information and data, if any issues arise, promptly inform the information and data receiving agency of the reasons and measures to address them.

4. Encourage the owners of specialized meteorological and hydrological works not covered under Clause 3, Article 13 of the Law on Meteorology and Hydrology to provide meteorological and hydrological observation information and data to the national weather forecasting and warning system.

Article 11. Information and data collection agencies

Article 11. Agencies Receiving Information and Data

1. The General Department of Meteorology and Hydrology, Ministry of Natural Resources and Environment receives specialized meteorological and hydrological observation information and data for the national weather forecasting and warning system and the national meteorological and hydrological database.

2. Provincial Departments of Natural Resources and Environment directly under the Central Government receive specialized meteorological and hydrological observation information and data within their respective localities.

3. Agencies receiving information and data have the responsibility:

a) To organize the receipt of information and data, check the list, quantity, structure, format, and level of information and data security;

b) When discovering that information and data do not meet safety requirements, are not provided at the correct time, do not conform to the structure and format, or do not match the specified list and quantity, the receiving agency shall immediately notify the organization or individual concerned to take corrective measures;

c) To report the results of receiving specialized meteorological and hydrological observation information and data.

Article 12. Time, Structure, and Method of Providing and Receiving Information and Data

1. Time of Provision:

a) Information and data provided to the national weather forecasting and warning system shall be carried out in accordance with Clause 2, Article 5 of Decree No. 38/2016/NĐ-CP;

b) Information and data provided to the national meteorological and hydrological database: once a year, before March 31 each year.

2. Structure of Provided Information and Data:

a) Structured and formatted numerical information and data shall comply with the provisions set forth in Appendix 4 attached to this Circular;

b) Textual information and data and other carriers of information shall be provided according to actual conditions.

3. Method of Provision:

a) The method of providing information and data to the national weather forecasting and warning system shall be carried out in accordance with Clause 4, Article 5 of Decree No. 38/2016/NĐ-CP;

Chapter III

IMPLEMENTATION

Article 13. Effective Date

b) The method of providing information and data to the national meteorological and hydrological database shall be carried out in accordance with Circular No. 07/2016/TT-BTNMT dated May 16, 2016 of the Minister of Natural Resources and Environment stipulating databases, data standards, and construction and management of the national meteorological and hydrological database.

Article 14. Responsibility for Implementation

1. Ministries, ministerial-level agencies, government-affiliated agencies, provincial People's Committees, and related agencies and organizations shall be responsible for implementing this Circular.

This Circular takes effect from February 11, 2019.