Editing IPCC:AR6/WGI/Chapter-Atlas (section)

=== Atlas.2.2 Description of the Interactive Atlas: Functionalities and Datasets ===

<div id="h2-10-siblings" class="h2-siblings"></div>

The Interactive Atlas builds on the work done in the context of the Spanish National Adaptation Plan (PNACC – AdapteCCa; [http://escenarios.adaptecca.es h ttp://escenarios .adaptecca.es] ) to develop an interactive online application centralizing and providing key regional climate change information to assist the Spanish climate change impact and adaptation community. The functionalities included in the AR6 WGI Interactive Atlas are an evolution of those implemented in AdapteCCa and have been adapted and extended to cope with the particular requirements of the datasets and functionalities it includes. In particular, the Interactive Atlas allows analysis of global and regional information on past trends and future climate changes through a wide range of maps, graphs and tables generated in an interactive manner, and building on six basic products (Figure Atlas.8):

# Global maps of ensemble mean values averaged over time slices across scenarios and GWLs, with robustness represented using the approaches described in Cross-Chapter Box Atlas.1.
# Temporal series, displaying all individual ensemble members and the multi-model median, with robustness represented as ranges across the ensemble (25th–75th and 10th–90th percentile ranges). The selected reference period of analysis is also displayed as context information, either a time slice (near, mid- or long term) or a GWL (defined for a given model as the first 20-year period where its average surface temperature change first reaches the GWL relative to its 1850–1900 temperature).
# Annual cycle plots representing individual models, the multi-model median and ranges across the ensemble.
# Stripe and seasonal stripe plots, providing visual information on changes across the ensemble (different models in rows with the multi-model median on the top) and across seasons (months in rows, using the signal from the multi-model mean), respectively.
# Two-variable scatter plots (e.g., temperature versus precipitation) and GWL plots representing regional/global changes of a particular variable versus global mean warming.
# Tables with summary information.

The first of these products provides spatial information about the ensemble mean, while the latter five convey (spatially) aggregated information of the multi-model ensemble for particular region(s) selected by the user from a number of predefined alternatives (see [[#Atlas.1.3.3|Atlas.1.3.3]] and [[#Atlas.1.3.4|Atlas.1.3.4]] for reference and typological regions, respectively).

The Interactive Atlas includes both atmospheric (daily mean, minimum and maximum temperatures, precipitation, snowfall and wind) and oceanic (sea surface temperature, pH, sea ice, and sea level rise) essential variables assessed in the Atlas chapter and Chapters 4, 8 and 9, as well as some derived extreme indices used in [[IPCC:Wg1:Chapter:Chapter-11|Chapter 11]] and a selection of CIDs used in [[IPCC:Wg1:Chapter:Chapter-12|Chapter 12]] (see Annex VI):

* Maximum of maximum temperatures (TXx) – see Chapter 11.
* Minimum of minimum temperatures (TNn) – see Chapter 11.
* Maximum 1-day precipitation (Rx1day) – see Chapter 11.
* Maximum 5-day precipitation (Rx5day) – see Chapter 11.
* Consecutive dry days (CDD) – see Chapter 11.
* Standardized Precipitation Index (SPI-6) – see Chapters 11 and 12.
* Frost days (FD), both raw and bias adjusted – see Chapters 11 and 12.
* Heating degree days (HD) – see Chapter 12.
* Cooling degree days (CD) – see Chapter 12.
* Days with maximum temperature above 35°C (TX35), both raw and bias adjusted – see Chapter 12.
* Days with maximum temperature above 40°C (TX40), both raw and bias adjusted – see Chapter 12.

The essential variables are computed for observations and reanalysis datasets as described in [[#Atlas.1.4.1|Atlas.1.4.1]] and [[#Atlas.1.4.2|Atlas.1.4.2]] (note that the Atlas does not include observational datasets for extremes). Trend analyses are available for two alternative baseline periods (1961–2015 and 1980–2015, selected according to data availability). This expands the information available in [[IPCC:Wg1:Chapter:Chapter-2|Chapter 2]] for global observational datasets, including new periods of analysis and new regional observational datasets which provide further insight into observational uncertainty. The Interactive Atlas also includes paleoclimate information from the Paleoclimate Model Intercomparison Projects PMIP3/4 for temperature and precipitation for the Last Glacial Maximum, Last Interglacial, mid-Holocene and mid-Pliocene periods (see Cross-Chapter Box 2.1).

Both essential variables and indices/CIDs are computed for CMIP5, CMIP6 and CORDEX model projections ( [[#Atlas.1.4.3|Atlas.1.4.3]] and [[#Atlas.1.4.4|Atlas.1.4.4]] ). The calculations are performed on the original model grids and results are interpolated to the reference regular grids at horizontal resolutions of 2° (CMIP5), 1° (CMIP6) and 0.5° (CORDEX) ( [[#Iturbide--2021|Iturbide et al., 2021]] ). Information is available for the historical, SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5 scenarios for CMIP6, and historical, RCP2.6, RCP4.5 and RCP8.5 for CMIP5 and CORDEX, as documented in the supplementary material Tables Atlas.SM.1–2 (for CMIP5/CMIP6) and Tables Atlas.SM.3–14 (for the different CORDEX domains). All products (maps, graphs and tables) are available for different reference periods of analysis, either time slices (2021–2040, 2041–2060 and 2081–2100 for near-, mid- and long-term future periods, respectively; see [[#Atlas.1.3.1|Atlas.1.3.1]] ), or GWLs (1.5°C, 2°C, 3°C or 4°C; see [[#Atlas.1.3.2|Atlas.1.3.2]] ), with changes relative to a number of alternative baselines (including 1850–1900 pre-industrial, and 1995–2014 recent past; see [[#Atlas.1.3.1|Atlas.1.3.1]] ). Note that instead of blending the information from the different scenarios, the Interactive Atlas allows comparison of the GWL spatial patterns and timings across the different scenarios (Cross-Chapter Box 11.1).

Some of the above indices (in particular, TX35 and TX40) are highly sensitive to model biases and the application of bias-adjustment techniques is recommended to alleviate this problem (see Cross-Chapter Box 10.2). Bias adjustment is performed as explained in [[#Atlas.1.4.5|Atlas.1.4.5]] .

The Interactive Atlas implements the approaches for representing robustness in maps at the grid-box level described in Cross-Chapter Box Atlas.1. These approaches are not necessarily informative for assessing trends and climate change signals over larger spatial scales where signals are less affected by small-scale variability leading to an increase in robustness. For regional analysis, the Interactive Atlas allows the analysis of aggregated region-wide signals and assessing their robustness at a regional scale, thus complementing the previous approach for grid-box robustness representation. For example, Figure Atlas.9 shows large hatched areas for maximum five-day precipitation in the South Asia region. When aggregated spatially, the region exhibits a robust wetting signal, with most ensemble members agreeing on the sign. This highlights that signals may not have emerged at the station or grid-box scale but have clearly at aggregated scales, particularly for variables with high variability (e.g., extreme precipitation or cold extremes; see Cross-Chapter Box Atlas.1).

<div id="_idContainer038" class="Basic-Text-Frame"></div>

[[File:1fefb0fff696d8c6351018051f5fe4de IPCC_AR6_WGI_Atlas_Figure_9.png]]

'''Figure Atlas.9''' '''|''' '''Analysing robustness and uncertainty in climate change signals across spatial scales using the Interactive Atlas.''' The left panel shows projected annual relative changes for maximum five-day precipitation from CMIP6 for 2081–2100 relative to a 1995-2014 baseline under the SSP3-7.0 scenario, through a map of the ensemble-mean changes (panel top) and information on the regional aggregated signal over the South Asia reference region as a time series (panel bottom). This shows non-robust changes (diagonal lines) at the grid-box level (due to the large local variability), but a robust aggregated signal over the region. The right panel shows projected surface wind-speed changes from CMIP6 models for 2041–2060 relative to a 1995–2014 baseline under the SSP5-8.5 scenario, again with the ensemble-mean changes in the map (panel top) and a regionally aggregated time series over Central Africa for each model (panel bottom). This shows conflicting changes (crossed lines) at the grid-box level due to signals of opposite sign in the individual models displayed in the time series.

The advanced approach for representing robustness includes a new category for identifying conflicting signals, where models are projecting significant changes but of opposite signs. This is demonstrated in Figure Atlas.9 which shows a region of central Africa where models have significant changes in surface winds with some projecting increases and others decreases. This is clearly demonstrated in the time series below the map which shows these wind-speed changes aggregated over the CAF reference region for each of the CMIP6 models and the opposing signals in many of these.

<div id="Atlas.2.3" class="h2-container"></div>

<span id="atlas.2.3-accessibility-reproducibility-and-reusability-fair-principles"></span>