The ClimaMonitor methodology is derived from the ClimaMeter methodology, detailed in Faranda et al. 2024.
Every day, we take the daily surface-pressure pattern over the North Atlantic. The methodology consists of looking for weather conditions similar (called analogues) to those of the present day with physics-informed methodologies. We focus on the historical data, namely the period since 1950.
We split the dataset into two parts of equal length and consider the first half of the historical period as "past" (not yet too much affected by human-induced climate change) and the second part as "present" (heavily affected by human-induced climate change) separately. We then compare how the selected weather conditions (surface-pressure, temperature, and precipitation) have changed between the two periods, and whether such changes are likely due to natural climate variability or anthropogenic climate change.
Differently from ClimaMeter, ClimaMonitor performs attribution for every day, regardless of whether extreme weather events occur. While ClimaMeter focuses on extremes (that are rare by definition), ClimaMonitor can assess normal weather patterns that do not necessarily lead to extreme events.
A confidence level, provided in the form of a three-star rating system, assesses whether the displayed changes in weather conditions can be attributed to human-induced climate change. This confidence level is based on two indices :
The rarity of the weather pattern. The more uncommon the weather pattern, the less likely it is to find good analogues of it in the reference periods. Without good analogues, the attribution analysis is invalid.
The role of natural variability. If major modes of climate variability (ENSO and AMO) were in different phases during similar past and present weather events, then natural variability might be partly influencing the changes we observe between the two periods.
The different possible confidence levels are:
☆☆☆ No confidence – Exceptional weather pattern; temperature/precipitation changes explained by natural variability.
★☆☆ Low confidence – Rare weather pattern; temperature/precipitation changes may be due to natural variability.
★★☆ Moderate confidence – Common weather pattern; natural variability alone cannot explain temperature/precipitation changes.
★★★ High confidence – Usual weather pattern; temperature/precipitation changes attributable to human-driven warming.
ClimaMonitor also provides city-specific information across the North Atlantic region, detailing how temperature and precipitation have changed between the past and the present in major cities.
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To better understand ClimaMonitor figures, check out the "Quick guide on how to read it" just above this section.
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The analyses are updated daily at around 13:00 CET.
