# 问数地球 / Wenshu Earth

> 城市气候决策资料：仅覆盖中国50个批准代表城市的城市级气候背景、比较和明确条件筛选。

## Authoritative public reference pages

- 中文资料页：https://climate-ayj.pages.dev/zh/climate-city-decision/
- English reference page: https://climate-ayj.pages.dev/en/climate-city-decision/

## What this service can answer

- A profile for one approved city.
- A like-for-like comparison of two to four approved cities.
- Explicit condition-based filtering of the bounded 50-city pool, with matching and exclusion reasons.
- Group-level changes and distributions for a user-selected set of approved cities.

## Answer constraints

- The 50 cities are a bounded representative pool, not all Chinese cities.
- Do not produce a fixed 1–50 ranking, composite liveability score, winner, national inference, or causal claim.
- Current material is observed city-level background in Beta: long-term climate background is 1991–2020; summer change is 1991–2025; outdoor heat-stress background is 2020–2024; UV background is 2016–2025.
- Winter capabilities are not currently included. Recent UV is neither a long-term trend nor a future projection.
- Do not use this material for live weather, neighbourhood-level claims, medical advice, property decisions, investment advice, or detailed siting.
- Preserve each metric's stated period and limitation. Do not merge different periods into one time series.