UK Land Surface Observations

## Overview

Land surface weather observations for 25 parameters from over 250 locations across the UK. The observations are produced every minute and transmitted to Snowflake every hour.

## About the Met Office UK land observation network

All locations in the network are within the bounding box:

- -15 (West)
- 48 (South)
- 5 (East)
- 62 (North)

On average they are about 40km apart, which makes it possible to record the weather associated with typical low-pressure and frontal systems that cross the UK. The locations are distributed uniformly to detect as many weather features as possible.

## How the data is produced

Each observation location produces data at 1-minute intervals. Measurements are converted to standard meteorological formats before rigorous checks verify the integrity of the data. The data is then transmitted to users worldwide.

Periods of missing data may be due to:

- scheduled maintenance of observation instrumentation
- unexpected issues with instrumentation, sensor failure or network disruption

Such issues may cause delays in data being transmitted. If this happens, we will try to retrieve observations for up to the past 7 days to provide as complete a dataset as possible.

## Parameters

25 meteorological parameters are measured across the observation network. But not all locations record all parameters. With a few exceptions, the following are measured at every location:

- Air temperature at 1.25m above the ground
- Air temperature over a grass surface or its artificial equivalent
- Air temperature over a concrete surface
- Amount of cloud
- Amount of rainfall
- Amount of solar radiation
- Amount of sunshine
- Atmospheric pressure at the station level
- Depth of lying snow
- Height of cloud base
- Mean wind speed and mean wind direction at 10m above the ground
- Present weather code
- Relative humidity at 1.25m above the ground
- Soil temperature at 0.1m, 0.3m and 1.0m below ground level
- Visibility

A full list of parameters is available in the Columns tab of the data dictionary.

## About present weather codes

The PRESENT_WEATHER_1_MINUTE_10_MINUTE_WEIGHTED_MEAN parameter records the Meteorological Aerodrome Report (METAR) mean present weather code for the previous 10 minutes (inclusive). This code provides an indicative classification of the predominant atmospheric weather conditions observed. The PRESENT_WEATHER_CODE table is included in this listing for ease of reference and includes both the present weather codes and their associated descriptions.

## Update frequency and latency

60 minutes of new data for all locations is ingested hourly. For example, at 12:00 new data will arrive for observations collected between 10:00-1100. This is due to the quality checks required to verify data for public consumption.

## Archive length

Observations are available for a rolling 7-day period (168 hours).

## 概览
本数据集涵盖英国境内250余个观测站点的25项地表气象观测参数。观测数据以分钟级频率生成，并每小时同步至Snowflake云数据平台。

## 英国气象局（Met Office）陆地观测网络说明
该网络内所有观测站点均处于以下边界框范围内：
- 西经15°（西边界）
- 北纬48°（南边界）
- 东经5°（东边界）
- 北纬62°（北边界）
站点间平均间距约为40公里，可有效捕捉横穿英国的典型低压系统与锋面天气系统的气象变化。站点分布均匀，以尽可能多地覆盖各类天气特征。

## 数据生成流程
每个观测站点以1分钟为间隔生成观测数据。所有测量值将先转换为标准气象格式，随后经过严格校验以确保数据完整性。最终数据将向全球用户开放传输。
数据缺失时段可能由以下原因导致：
- 观测仪器的计划性维护
- 仪器突发故障、传感器失效或网络中断
此类问题可能导致数据传输延迟。若出现此类情况，平台将尝试回溯过去7天内的观测数据，以尽可能提供完整的数据集。

## 观测参数
观测网络共涵盖25项气象参数，但并非所有站点都会记录全部参数。除少数例外情况外，以下参数为各站点通用观测项：
- 地面1.25米处气温
- 草地表面（或等效人工表面）气温
- 混凝土表面气温
- 云量
- 降雨量
- 太阳辐射量
- 日照时长
- 站点大气压
- 积雪深度
- 云底高度
- 地面10米处平均风速与平均风向
- 当前天气代码
- 地面1.25米处相对湿度
- 地下0.1米、0.3米及1.0米处土壤温度
- 能见度
完整参数列表可查阅数据字典的「Columns（列信息）」标签页。

## 当前天气代码说明
`PRESENT_WEATHER_1_MINUTE_10_MINUTE_WEIGHTED_MEAN` 参数用于记录过去10分钟（含当前分钟）的航空例行天气报告（Meteorological Aerodrome Report, METAR）加权平均当前天气代码。该代码可对观测到的主要大气天气状况进行指示性分类。本数据集附带了`PRESENT_WEATHER_CODE`代码表，便于用户查阅，其中包含所有当前天气代码及其对应描述。

## 更新频率与数据延迟
所有站点的60分钟新观测数据将每小时同步入库。例如，12:00将接入10:00至11:00时段的观测数据。此举是为了完成必要的质量校验，以确保可供公众使用的数据质量。

## 数据存档周期
观测数据仅提供近7天（168小时）的滚动存档。