Tier II: Mean state and trends — temperature (2m, surface)

## Description
Score models on mean state and trends of near-surface and surface temperature.

## Specification
- 2m temperature: seasonal (DJF, MAM, JJA, SON) and annual mean state + trends
- Surface temperature: seasonal and annual (HadSST/HadISST for ocean, CRU TS for land)
- Test period: post-2015
- Metrics: CRPS (ensemble), NRMSE and spatial correlation (deterministic)
- Extremes: 5th and 95th percentiles of daily distribution

## Observational datasets
NASA GISS, Berkeley Earth, HadCRUT, NOAA GlobalTemp, HadSST, HadISST, CRU TS, HadGHCND, Berkeley Earth (daily)

## Required simulations
historical (updated), ≥3 ensemble members