library(epwshiftr)

if (!exists("shift_request", mode = "function")) {
    stop(
        "This raw article must be rendered from the package source with ",
        "`tools/render-raw-vignettes.R`.",
        call. = FALSE
    )
}

This article is the recommended main workflow for epwshiftr. It runs a real store-native shift workflow from ESGF File records to generated EPW files. It uses monthly Amon data so the live remote reads are much smaller than an equivalent daily workflow.

The examples below use the high-level shift_*() facade. When a step touches a lower-level engine, this article links to the companion article for that layer: ESGF query results, ESG dictionaries, ESG stores, Downloader, EpwMorpher, CLI operations, and ESGF troubleshooting.

Use a temporary store for this article run. For a real project, replace this with a persistent project cache path.

workflow_root <- file.path(tempdir(), "epwshiftr-future-epw-workflow")
if (dir.exists(workflow_root)) {
    unlink(workflow_root, recursive = TRUE)
}
dir.create(workflow_root, recursive = TRUE, showWarnings = FALSE)

options(
    epwshiftr.dir_cache = file.path(workflow_root, "cache")
)

Site and Request

shift_site() describes the location that will be extracted from climate projection data. The id is the stable site key used in extraction plans, manifest rows, and output naming, so use a short value that will still make sense when you process several sites.

This article writes a deterministic Singapore baseline EPW into the temporary workflow directory so the raw render is self-contained. The climate query and remote data reads below still use live ESGF services.

You can provide the site metadata directly:

epw <- write_vignette_epw(
    file.path(workflow_root, "baseline", "SGP_Singapore.486980_IWEC.epw")
)

site <- shift_site(
    id = "SIN",
    lon = 103.98,
    lat = 1.37,
    label = "Singapore"
)

site
#> <ShiftSite>
#>   id:     SIN
#>   lonlat: 103.980000, 1.370000
#>   label:  Singapore

Or you can read the same information from an eplusr::Epw object:

epw_site <- shift_site(eplusr::read_epw(epw))
epw_site
#> <ShiftSite>
#>   id:     486980
#>   lonlat: 103.980000, 1.370000
#>   label:  Singapore
#>   epw:    Epw

This article keeps using the explicit site object so the site ID is short and predictable, while the EPW file itself is passed later as the morphing baseline.

epw_morph_variables() returns the CMIP variable IDs needed by the selected morphing recipe. The result is a plain character vector because the same variable IDs are used at several workflow stages: first as the ESGF variable_id filter in shift_request(), then as the extraction variable list in shift_extract(), and finally as the coverage check used by shift_morph().

The helper provides three named variable sets:

  • "minimal": air temperature and relative humidity, useful for relaxed demonstrations.
  • "recommended": the current strict Belcher recipe set, including precipitation.
  • "extended": the recommended set plus related max/min variables for future recipes.

This article uses the default Belcher recipe. It is a change-factor backend, so the morphing step needs both a future climate extraction and a reference climate extraction.

shift_recipe <- epw_morph_recipe("belcher")
variables <- epw_morph_variables(shift_recipe)
variables
#> [1] "tas"     "hurs"    "psl"     "rlds"    "rsds"    "sfcWind" "clt"
#> [8] "pr"

shift_request() describes the remote climate data you want. The future request targets one ESGF ScenarioMIP model, scenario, member, and monthly table. The reference request uses the matching historical experiment so Belcher change-factor morphing can compare future monthly fields with reference monthly fields before applying those changes to the baseline EPW.

The values inside filters are ESGF search fields. options is not a search filter. options$index_node chooses the ESGF search node; if omitted, epwshiftr uses its default ESGF index. The other request option currently recognized by the ESGF adapter is time_filter_method, which controls how File records are filtered by time after Dataset collection; the default is "drs" filename parsing. The time argument narrows File records after Dataset collection; it does not mean the whole period is downloaded. A numeric year such as 2060L is expanded to that whole calendar year.

Read more about the lower-level query object in ESGF query results, and about request-value validation in ESG dictionaries.

request <- shift_request(
    project = "CMIP6",
    time = 2060L,
    filters = list(
        activity_id = "ScenarioMIP",
        source_id = "MPI-ESM1-2-LR",
        experiment_id = "ssp585",
        variant_label = "r1i1p1f1",
        frequency = "mon",
        variable_id = variables,
        data_node = "esgf.ceda.ac.uk",
        table_id = "Amon"
    ),
    options = list(index_node = "https://esgf-data.dkrz.de")
)

request
#> <epwshiftr::ShiftRequest>
#>   stage:  request
#>   status: new
#>   project: CMIP6
#>   source: MPI-ESM1-2-LR
#>   experiment: ssp585
#>   variant: r1i1p1f1
#>   frequency: mon
#>   variables: tas, hurs, psl, rlds, rsds, sfcWind, clt, ... (8 total)
#>   time:   2060-01-01T00:00:00Z -> 2060-12-31T23:59:59Z

reference_request <- shift_request(
    project = "CMIP6",
    time = 1995L,
    filters = list(
        activity_id = "CMIP",
        source_id = "MPI-ESM1-2-LR",
        experiment_id = "historical",
        variant_label = "r1i1p1f1",
        frequency = "mon",
        variable_id = variables,
        data_node = "esgf.ceda.ac.uk",
        table_id = "Amon"
    ),
    options = list(index_node = "https://esgf-data.dkrz.de")
)

reference_request

Run the Workflow

The diagram below is the map for the rest of the article. Each shift_*() call returns a stage object that can be printed, checked, and passed to the next step.

shift_download() is optional. Use it when you want to prefetch full NetCDF files for offline work, repeated extraction, or unstable OPeNDAP access.

The ordinary path goes directly from collected File records to extraction. Full NetCDF downloads are not required unless you intentionally want a local source-file cache.

Inspect Dataset Matches

Before collecting File records, inspect the Dataset matches. If this table is broader or narrower than intended, change the request filters before continuing. shift_datasets() runs the Dataset-level ESGF search described by shift_request(). The returned EsgResultDataset object is not the data to download yet; it is the list of Dataset records that will later be expanded into File records.

For a deeper look at Dataset, File, and Aggregation results, see ESGF query results.

datasets <- shift_datasets(request)
datasets
#> [1] CMIP6.ScenarioMIP.MPI-M.MPI-ESM1-2-LR.ssp585.r1i1p1f1.Amon.clt.gn.v20190710|esgf.ceda.ac.uk
#>     [ 5 Files, 50.15 MiB | No Aggregations ]
#>     [ Access: <HTTPServer, OPENDAP> ]
#> [2] CMIP6.ScenarioMIP.MPI-M.MPI-ESM1-2-LR.ssp585.r1i1p1f1.Amon.hurs.gn.v20190815|esgf.ceda.ac.uk
#>     [ 5 Files, 45.55 MiB | No Aggregations ]
#>     [ Access: <HTTPServer, OPENDAP> ]
#> [3] CMIP6.ScenarioMIP.MPI-M.MPI-ESM1-2-LR.ssp585.r1i1p1f1.Amon.psl.gn.v20190710|esgf.ceda.ac.uk
#>     [ 5 Files, 33.85 MiB | No Aggregations ]
#>     [ Access: <HTTPServer, OPENDAP> ]
#> [4] CMIP6.ScenarioMIP.MPI-M.MPI-ESM1-2-LR.ssp585.r1i1p1f1.Amon.rlds.gn.v20190710|esgf.ceda.ac.uk
#>     [ 5 Files, 37.41 MiB | No Aggregations ]
#>     [ Access: <HTTPServer, OPENDAP> ]
#> [5] CMIP6.ScenarioMIP.MPI-M.MPI-ESM1-2-LR.ssp585.r1i1p1f1.Amon.rsds.gn.v20190710|esgf.ceda.ac.uk
#>     [ 5 Files, 36.4 MiB | No Aggregations ]
#>     [ Access: <HTTPServer, OPENDAP> ]
#> [6] CMIP6.ScenarioMIP.MPI-M.MPI-ESM1-2-LR.ssp585.r1i1p1f1.Amon.sfcWind.gn.v20190710|esgf.ceda.ac.uk
#>     [ 5 Files, 40.27 MiB | No Aggregations ]
#>     [ Access: <HTTPServer, OPENDAP> ]
#> [7] CMIP6.ScenarioMIP.MPI-M.MPI-ESM1-2-LR.ssp585.r1i1p1f1.Amon.tas.gn.v20190710|esgf.ceda.ac.uk
#>     [ 5 Files, 32.91 MiB | No Aggregations ]
#>     [ Access: <HTTPServer, OPENDAP> ]

Use $to_data_table() when you want row-level details for decisions such as whether the request matched the expected variables, model, variant, and data node.

dataset_table <- datasets$to_data_table(fields = c(
    "id", "source_id", "experiment_id", "variant_label",
    "variable_id", "data_node", "number_of_files"
), formatted = TRUE)

dataset_table
#>                                                                                                 id
#>                                                                                             <char>
#> 1:     CMIP6.ScenarioMIP.MPI-M.MPI-ESM1-2-LR.ssp585.r1i1p1f1.Amon.clt.gn.v20190710|esgf.ceda.ac.uk
#> 2:    CMIP6.ScenarioMIP.MPI-M.MPI-ESM1-2-LR.ssp585.r1i1p1f1.Amon.hurs.gn.v20190815|esgf.ceda.ac.uk
#> 3:     CMIP6.ScenarioMIP.MPI-M.MPI-ESM1-2-LR.ssp585.r1i1p1f1.Amon.psl.gn.v20190710|esgf.ceda.ac.uk
#> 4:    CMIP6.ScenarioMIP.MPI-M.MPI-ESM1-2-LR.ssp585.r1i1p1f1.Amon.rlds.gn.v20190710|esgf.ceda.ac.uk
#> 5:    CMIP6.ScenarioMIP.MPI-M.MPI-ESM1-2-LR.ssp585.r1i1p1f1.Amon.rsds.gn.v20190710|esgf.ceda.ac.uk
#> 6: CMIP6.ScenarioMIP.MPI-M.MPI-ESM1-2-LR.ssp585.r1i1p1f1.Amon.sfcWind.gn.v20190710|esgf.ceda.ac.uk
#> 7:     CMIP6.ScenarioMIP.MPI-M.MPI-ESM1-2-LR.ssp585.r1i1p1f1.Amon.tas.gn.v20190710|esgf.ceda.ac.uk
#>        source_id experiment_id variant_label variable_id       data_node
#>           <char>        <char>        <char>      <char>          <char>
#> 1: MPI-ESM1-2-LR        ssp585      r1i1p1f1         clt esgf.ceda.ac.uk
#> 2: MPI-ESM1-2-LR        ssp585      r1i1p1f1        hurs esgf.ceda.ac.uk
#> 3: MPI-ESM1-2-LR        ssp585      r1i1p1f1         psl esgf.ceda.ac.uk
#> 4: MPI-ESM1-2-LR        ssp585      r1i1p1f1        rlds esgf.ceda.ac.uk
#> 5: MPI-ESM1-2-LR        ssp585      r1i1p1f1        rsds esgf.ceda.ac.uk
#> 6: MPI-ESM1-2-LR        ssp585      r1i1p1f1     sfcWind esgf.ceda.ac.uk
#> 7: MPI-ESM1-2-LR        ssp585      r1i1p1f1         tas esgf.ceda.ac.uk
#>    number_of_files
#>              <int>
#> 1:               5
#> 2:               5
#> 3:               5
#> 4:               5
#> 5:               5
#> 6:               5
#> 7:               5

Summarise the table before moving on. In this request, each variable should have one matching Dataset record on the selected data node.

dataset_table[, .(
    datasets = .N,
    files = sum(number_of_files, na.rm = TRUE),
    variables = paste(sort(unique(variable_id)), collapse = ", ")
), by = .(source_id, experiment_id, variant_label, data_node)]
#>        source_id experiment_id variant_label       data_node datasets files
#>           <char>        <char>        <char>          <char>    <int> <int>
#> 1: MPI-ESM1-2-LR        ssp585      r1i1p1f1 esgf.ceda.ac.uk        7    35
#>                                   variables
#>                                      <char>
#> 1: clt, hurs, psl, rlds, rsds, sfcWind, tas

The Dataset result can also be filtered locally before collecting child File records. This is useful when a broad request intentionally returns several models, variants, data nodes, or variables and you want to inspect or keep only part of the match. The example below keeps only two variables so the effect is easy to see.

selected_datasets <- datasets$filter(function(x) {
    x$variable_id %in% c("tas", "hurs")
})

selected_datasets$to_data_table(fields = c(
    "id", "variable_id", "data_node", "number_of_files"
))
#>                                                                                              id
#>                                                                                          <char>
#> 1: CMIP6.ScenarioMIP.MPI-M.MPI-ESM1-2-LR.ssp585.r1i1p1f1.Amon.hurs.gn.v20190815|esgf.ceda.ac.uk
#> 2:  CMIP6.ScenarioMIP.MPI-M.MPI-ESM1-2-LR.ssp585.r1i1p1f1.Amon.tas.gn.v20190710|esgf.ceda.ac.uk
#>    variable_id       data_node number_of_files
#>         <char>          <char>           <int>
#> 1:        hurs esgf.ceda.ac.uk               5
#> 2:         tas esgf.ceda.ac.uk               5

For a lower-level workflow, you can collect File records from that subset directly. The staged shift_collect() call below performs the same Dataset-to-File expansion for the original request and stores the result in an EsgStore, so the main workflow continues with shift_collect().

selected_files <- selected_datasets$collect(
    type = "File",
    fields = "*",
    all = TRUE,
    limit = NULL
)

Collect File Records

store is the local directory where epwshiftr records ESGF File metadata, download tasks, extraction outputs, morphing factors, and generated EPWs. shift_collect() first collects Dataset records, then uses Dataset$collect(type = "File") to collect the concrete files needed by the rest of the workflow. The returned ShiftFiles object is the workflow stage: it remembers the store path and internal query ID so later steps do not need the user to pass file paths or manifest IDs.

For store internals such as query snapshots, file catalogs, artifacts, and tracked updates, see ESG stores.

files <- shift_collect(
    request,
    store = file.path(workflow_root, "singapore-store")
)

files
#> <epwshiftr::ShiftFiles>
#>   stage:  files
#>   status: collected
#>   store:  <tempdir>/epwshiftr-future-epw-workflow/singapore-store
#>   files:  7
#>   variables: clt, hurs, psl, rlds, rsds, sfcWind, tas
#>   ids:    query_id

reference_files <- shift_collect(
    reference_request,
    store = file.path(workflow_root, "singapore-store")
)

reference_files

Use shift_files() when you want to inspect the underlying EsgResultFile object that was saved into the store. Printing it gives the same high-level summary as a direct ESGF File query result.

file_result <- shift_files(files)
file_result
#> [1] CMIP6.ScenarioMIP.MPI-M.MPI-ESM1-2-LR.ssp585.r1i1p1f1.Amon.clt.gn.v20190710.clt_Amon_MPI-ESM1-2-LR_ssp585_r1i1p1f1_gn_205501-207412.nc|esgf.ceda.ac.uk
#>     [ 11.65 MiB | Access: <HTTPServer, OPENDAP> ]
#> [2] CMIP6.ScenarioMIP.MPI-M.MPI-ESM1-2-LR.ssp585.r1i1p1f1.Amon.hurs.gn.v20190815.hurs_Amon_MPI-ESM1-2-LR_ssp585_r1i1p1f1_gn_205501-207412.nc|esgf.ceda.ac.uk
#>     [ 10.58 MiB | Access: <HTTPServer, OPENDAP> ]
#> [3] CMIP6.ScenarioMIP.MPI-M.MPI-ESM1-2-LR.ssp585.r1i1p1f1.Amon.psl.gn.v20190710.psl_Amon_MPI-ESM1-2-LR_ssp585_r1i1p1f1_gn_205501-207412.nc|esgf.ceda.ac.uk
#>     [ 7.86 MiB | Access: <HTTPServer, OPENDAP> ]
#> [4] CMIP6.ScenarioMIP.MPI-M.MPI-ESM1-2-LR.ssp585.r1i1p1f1.Amon.rlds.gn.v20190710.rlds_Amon_MPI-ESM1-2-LR_ssp585_r1i1p1f1_gn_205501-207412.nc|esgf.ceda.ac.uk
#>     [ 8.68 MiB | Access: <HTTPServer, OPENDAP> ]
#> [5] CMIP6.ScenarioMIP.MPI-M.MPI-ESM1-2-LR.ssp585.r1i1p1f1.Amon.rsds.gn.v20190710.rsds_Amon_MPI-ESM1-2-LR_ssp585_r1i1p1f1_gn_205501-207412.nc|esgf.ceda.ac.uk
#>     [ 8.44 MiB | Access: <HTTPServer, OPENDAP> ]
#> [6] CMIP6.ScenarioMIP.MPI-M.MPI-ESM1-2-LR.ssp585.r1i1p1f1.Amon.sfcWind.gn.v20190710.sfcWind_Amon_MPI-ESM1-2-LR_ssp585_r1i1p1f1_gn_205501-207412.nc|esgf.ceda.ac.uk
#>     [ 9.35 MiB | Access: <HTTPServer, OPENDAP> ]
#> [7] CMIP6.ScenarioMIP.MPI-M.MPI-ESM1-2-LR.ssp585.r1i1p1f1.Amon.tas.gn.v20190710.tas_Amon_MPI-ESM1-2-LR_ssp585_r1i1p1f1_gn_205501-207412.nc|esgf.ceda.ac.uk
#>     [ 7.64 MiB | Access: <HTTPServer, OPENDAP> ]

Convert the File result to a table when you want to inspect exactly which files were found. The URL columns are long, so this view shows whether each file has OPeNDAP and HTTPServer access instead of printing the full URLs.

file_table <- file_result$to_data_table(fields = c(
    "filename", "variable_id", "data_node", "size",
    "url_opendap", "url_download"
), formatted = TRUE)

file_table[, .(
    filename,
    variable_id,
    data_node,
    size,
    opendap = !is.na(url_opendap) & nzchar(url_opendap),
    http = !is.na(url_download) & nzchar(url_download)
)]
#>                                                          filename variable_id
#>                                                            <char>      <char>
#> 1:     clt_Amon_MPI-ESM1-2-LR_ssp585_r1i1p1f1_gn_205501-207412.nc         clt
#> 2:    hurs_Amon_MPI-ESM1-2-LR_ssp585_r1i1p1f1_gn_205501-207412.nc        hurs
#> 3:     psl_Amon_MPI-ESM1-2-LR_ssp585_r1i1p1f1_gn_205501-207412.nc         psl
#> 4:    rlds_Amon_MPI-ESM1-2-LR_ssp585_r1i1p1f1_gn_205501-207412.nc        rlds
#> 5:    rsds_Amon_MPI-ESM1-2-LR_ssp585_r1i1p1f1_gn_205501-207412.nc        rsds
#> 6: sfcWind_Amon_MPI-ESM1-2-LR_ssp585_r1i1p1f1_gn_205501-207412.nc     sfcWind
#> 7:     tas_Amon_MPI-ESM1-2-LR_ssp585_r1i1p1f1_gn_205501-207412.nc         tas
#>          data_node            size opendap   http
#>             <char>         <units>  <lgcl> <lgcl>
#> 1: esgf.ceda.ac.uk 11.652859 [MiB]    TRUE   TRUE
#> 2: esgf.ceda.ac.uk 10.582312 [MiB]    TRUE   TRUE
#> 3: esgf.ceda.ac.uk  7.863685 [MiB]    TRUE   TRUE
#> 4: esgf.ceda.ac.uk  8.684435 [MiB]    TRUE   TRUE
#> 5: esgf.ceda.ac.uk  8.441223 [MiB]    TRUE   TRUE
#> 6: esgf.ceda.ac.uk  9.353412 [MiB]    TRUE   TRUE
#> 7: esgf.ceda.ac.uk  7.640529 [MiB]    TRUE   TRUE

Optional: Prefetch NetCDF Files

For the normal single-site workflow, you can skip shift_download() and go directly to shift_extract(). Extraction opens the OPeNDAP URL first and reads only the requested site, variables, and time range before storing the extracted result as Parquet.

shift_download() is useful when you deliberately want a complete local copy of the original ESGF NetCDF files before extraction. It downloads full source files through selected HTTPServer URLs into the store’s downloads/ directory. This is different from OPeNDAP, which lets shift_extract() read only the requested site, variables, and time range.

Use this optional prefetch step when you plan to reuse the same source files for many sites or periods, need offline extraction later, or expect OPeNDAP to be unavailable or unstable.

By default, shift_download() runs in the foreground (run = TRUE, background = FALSE). In an interactive session, keep progress = TRUE to see per-file progress bars. This article sets progress = FALSE only to keep the precompiled output compact.

If the network drops, the downloader keeps partial .part files and resume = TRUE lets the next run continue where possible. If the final file is already present and complete, it is reused. Use overwrite = TRUE only when you want to discard an existing completed file and download it again.

If a data node becomes unstable, rerun shift_download() with the same stage. The store keeps the File records and download session metadata, while the downloader records task status and data-node history. If you run the optional chunk below, inspect the result with shift_status(downloads), shift_check(downloads), and data.table::as.data.table(downloads).

For persistent sessions, background jobs, daemon mode, retries, and node history, see Downloader. For the same operations from a terminal, see CLI operations.

downloads <- shift_download(
    files,
    replica = "current",
    service = "HTTPServer",
    strategy = "stable",
    probe = FALSE,
    progress = FALSE
)

downloads

Extract Site Climate

This is where the remote climate data are actually read in the default workflow. shift_extract() opens OPeNDAP when possible, extracts only the requested site and period, and stores the extracted rows as Parquet artifacts in the store. In the code below the result is named extracted because it is the extracted site-level climate stage. Its class is ShiftClimate, because that stage is the climate data that shift_morph() will summarise and compare with the baseline EPW.

epw_morph_periods() maps user-facing period labels to one or more years. The name, such as 2060s, becomes the period label in summaries, morphing cases, and output paths. The numeric value is the year or years used to calculate that period. This article uses one year so the remote extraction stays small:

epw_morph_periods(`2060s` = 2060L)

A wider period is also valid, for example:

epw_morph_periods(`2060s` = 2055:2064)

The collected files must cover every year used by the period.

fallback = "auto" means extraction tries OPeNDAP first and may fall back to HTTP file downloads when remote OPeNDAP access is unavailable. Use "error" when you want remote access failures to stop the extraction instead.

Extraction is recorded in the local EsgStore; see ESG stores for the lower-level API. If OPeNDAP, data-node, or coverage problems appear, see ESGF troubleshooting.

periods <- epw_morph_periods(`2060s` = 2060L)
reference_periods <- epw_morph_periods(reference = 1995L)

extracted <- shift_extract(
    files,
    site = site,
    periods = periods,
    variables = variables,
    fallback = "auto"
)

extracted
#> <epwshiftr::ShiftClimate>
#>   stage:  climate
#>   status: extracted
#>   store:  <tempdir>/epwshiftr-future-epw-workflow/singapore-store
#>   coverage: 7/7 complete
#>   ids:    query_id, plan_id

reference <- shift_extract(
    reference_files,
    site = site,
    periods = reference_periods,
    variables = variables,
    fallback = "auto"
)

reference

shift_coverage() checks whether every requested variable has extracted rows for the selected site and period. This is the main sanity check before morphing.

coverage <- shift_coverage(extracted)
coverage[, .(variable_id, complete, status, output_rows, output_file_count)]
#>    variable_id complete status output_rows output_file_count
#>         <char>   <lgcl> <char>       <int>             <int>
#> 1:        rlds     TRUE   done          12                 1
#> 2:        rsds     TRUE   done          12                 1
#> 3:         psl     TRUE   done          12                 1
#> 4:         tas     TRUE   done          12                 1
#> 5:         clt     TRUE   done          12                 1
#> 6:     sfcWind     TRUE   done          12                 1
#> 7:        hurs     TRUE   done          12                 1

The extracted values are not stored inside the small stage object. They are written as partitioned Parquet files under the store and registered in the store manifest. shift_artifacts() shows those registered files:

extract_artifacts <- shift_artifacts(extracted)
extract_artifacts[kind == "extract", .(kind, role, relative_path)]
#>       kind    role
#>     <char>  <char>
#> 1: extract derived
#> 2: extract derived
#> 3: extract derived
#> 4: extract derived
#> 5: extract derived
#> 6: extract derived
#> 7: extract derived
#>                                                                                                                                                                                                           relative_path
#>                                                                                                                                                                                                                  <char>
#> 1:     extracts/project=CMIP6/source_id=MPI-ESM1-2-LR/experiment_id=ssp585/variant_label=r1i1p1f1/frequency=mon/variable_id=clt/year=2060/part-d442dc702cdbdbb9df13f618bef50a49fe8cbdb6391357d637cbbfcc4e1d02ad.parquet
#> 2:    extracts/project=CMIP6/source_id=MPI-ESM1-2-LR/experiment_id=ssp585/variant_label=r1i1p1f1/frequency=mon/variable_id=hurs/year=2060/part-d8f84ee054ee73ba2c20a6bbcd155510eea876556d4c1a08a1324d496b72b7ab.parquet
#> 3:     extracts/project=CMIP6/source_id=MPI-ESM1-2-LR/experiment_id=ssp585/variant_label=r1i1p1f1/frequency=mon/variable_id=psl/year=2060/part-53c9ac1d43c5aff19881432f5380a5d10dba8fb0952df8fd7f30a7d027ad0922.parquet
#> 4:    extracts/project=CMIP6/source_id=MPI-ESM1-2-LR/experiment_id=ssp585/variant_label=r1i1p1f1/frequency=mon/variable_id=rlds/year=2060/part-0529c672b2743d596b4ce567f20bc7da8679879d78416f84bbfa6a1c9d833bb3.parquet
#> 5:    extracts/project=CMIP6/source_id=MPI-ESM1-2-LR/experiment_id=ssp585/variant_label=r1i1p1f1/frequency=mon/variable_id=rsds/year=2060/part-47485cadca0ce1317db7c1cf9db32e49dfa14fe931ee7b9aaa7a295f2167f38e.parquet
#> 6: extracts/project=CMIP6/source_id=MPI-ESM1-2-LR/experiment_id=ssp585/variant_label=r1i1p1f1/frequency=mon/variable_id=sfcWind/year=2060/part-d7e5fe8f877b0fd8ce0ec12d3c7fec7e446804f67338fdbbdf6acd7b08a93aef.parquet
#> 7:     extracts/project=CMIP6/source_id=MPI-ESM1-2-LR/experiment_id=ssp585/variant_label=r1i1p1f1/frequency=mon/variable_id=tas/year=2060/part-7d32f39b9de114229f4abf5d8255ec18fdcbc882887b22ccb212ed4444dd303f.parquet

Use shift_data() when you want to inspect the actual extracted table without manually finding or reading those Parquet files. By default it returns a preview instead of loading everything into memory.

extracted_data <- shift_data(
    extracted,
    n = 20L,
    columns = c("site_id", "variable_id", "time", "lon", "lat", "value", "units")
)

extracted_data
#>     site_id variable_id                time     lon     lat    value  units
#>      <char>      <char>              <POSc>   <num>   <num>    <num> <char>
#>  1:     SIN         clt 2060-01-16 12:00:00 103.125 0.93263 82.30624      %
#>  2:     SIN         clt 2060-02-15 12:00:00 103.125 0.93263 64.81476      %
#>  3:     SIN         clt 2060-03-16 12:00:00 103.125 0.93263 57.06557      %
#>  4:     SIN         clt 2060-04-16 00:00:00 103.125 0.93263 45.10655      %
#>  5:     SIN         clt 2060-05-16 12:00:00 103.125 0.93263 58.98287      %
#>  6:     SIN         clt 2060-06-16 00:00:00 103.125 0.93263 87.22534      %
#>  7:     SIN         clt 2060-07-16 12:00:00 103.125 0.93263 92.17834      %
#>  8:     SIN         clt 2060-08-16 12:00:00 103.125 0.93263 87.00104      %
#>  9:     SIN         clt 2060-09-16 00:00:00 103.125 0.93263 93.51807      %
#> 10:     SIN         clt 2060-10-16 12:00:00 103.125 0.93263 80.29469      %
#> 11:     SIN         clt 2060-11-16 00:00:00 103.125 0.93263 63.98064      %
#> 12:     SIN         clt 2060-12-16 12:00:00 103.125 0.93263 88.22657      %
#> 13:     SIN        hurs 2060-01-16 12:00:00 103.125 0.93263 87.63216      %
#> 14:     SIN        hurs 2060-02-15 12:00:00 103.125 0.93263 79.58945      %
#> 15:     SIN        hurs 2060-03-16 12:00:00 103.125 0.93263 76.78159      %
#> 16:     SIN        hurs 2060-04-16 00:00:00 103.125 0.93263 81.37238      %
#> 17:     SIN        hurs 2060-05-16 12:00:00 103.125 0.93263 76.57287      %
#> 18:     SIN        hurs 2060-06-16 00:00:00 103.125 0.93263 80.83648      %
#> 19:     SIN        hurs 2060-07-16 12:00:00 103.125 0.93263 79.76086      %
#> 20:     SIN        hurs 2060-08-16 12:00:00 103.125 0.93263 81.98067      %
#>     site_id variable_id                time     lon     lat    value  units
#>      <char>      <char>              <POSc>   <num>   <num>    <num> <char>

Morph Hourly Weather

shift_morph() summarises the extracted monthly climate, compares it with the baseline EPW, creates morphing factors, and writes morphed hourly results back to the store. With strict = TRUE, missing required variables or incomplete coverage are blocking errors instead of warnings.

shift_morph() wraps the lower-level EpwMorpher planning and execution API. See EpwMorpher when you need to inspect monthly summaries, factor diagnostics, case grouping, or custom backend registration.

For Belcher change-factor morphing, pass either an extracted historical ShiftClimate stage or an automatic reference spec such as shift_reference_historical(reference_periods).

The same shift_recipe used to choose request variables can be passed into shift_morph(). Adjust the recipe when you want to change Belcher methods or select another registered backend:

shift_recipe <- epw_morph_recipe(
    "belcher",
    methods = c(tdb = "shift", rh = "shift")
)

shift_morph(
    extracted,
    reference = reference,
    baseline = epw,
    recipe = shift_recipe,
    strict = TRUE
)
morphed <- shift_morph(
    extracted,
    reference = reference,
    baseline = epw,
    recipe = shift_recipe,
    strict = TRUE
)

morphed
#> <epwshiftr::ShiftMorphed>
#>   stage:  morphed
#>   status: morphed
#>   store:  <tempdir>/epwshiftr-future-epw-workflow/singapore-store
#>   morph: planned
#>   cases:  1
#>   ids:    query_id, plan_id, summary_id, baseline_id, morph_id

The morphed stage is still store-native. It contains hourly future weather data as Parquet artifacts, not EPW text files yet. Inspect the artifact rows when you want to see where those intermediate results live:

morph_artifacts <- shift_artifacts(morphed)
morph_artifacts[, .(kind, role, relative_path)]
#>      kind    role
#>    <char>  <char>
#> 1: output derived
#>                                                                                                                                                       relative_path
#>                                                                                                                                                              <char>
#> 1: outputs/epw-morph/7151ba639a04006fccc4809f2754db0c5111217b4b2083cb7cc8c02bb90875ca/case=449d8e0e3db38f5e39681257d5f5c78d802a31e5bdcaeb40f9045f798938b76e.parquet

Use the same shift_data() helper to preview the hourly morphed weather table. The metadata columns identify the morphing case; the weather columns are the hourly EPW-style values that will be written to the final EPW. The preview below omits long IDs to keep the table readable; include case_id in columns when you need to join rows back to a specific morphing case.

morphed_data <- shift_data(
    morphed,
    n = 24L,
    columns = c(
        "period", "year", "month", "day", "hour",
        "dry_bulb_temperature", "relative_humidity", "wind_speed"
    )
)

morphed_data
#>     period  year month   day  hour dry_bulb_temperature relative_humidity
#>     <char> <int> <int> <int> <int>                <num>             <num>
#>  1:  2060s  2001     1     1     1             23.91930          98.86706
#>  2:  2060s  2001     1     1     2             23.81837         100.00000
#>  3:  2060s  2001     1     1     3             23.71744         100.00000
#>  4:  2060s  2001     1     1     4             23.81837         100.00000
#>  5:  2060s  2001     1     1     5             23.91930          98.86706
#>  6:  2060s  2001     1     1     6             24.22207          96.62008
#>  7:  2060s  2001     1     1     7             24.52485          94.37310
#>  8:  2060s  2001     1     1     8             24.82762          91.00263
#>  9:  2060s  2001     1     1     9             25.23132          87.63216
#> 10:  2060s  2001     1     1    10             25.63503          84.26170
#> 11:  2060s  2001     1     1    11             26.03873          80.89123
#> 12:  2060s  2001     1     1    12             26.34150          78.64425
#> 13:  2060s  2001     1     1    13             26.54335          76.39727
#> 14:  2060s  2001     1     1    14             26.74520          74.15029
#> 15:  2060s  2001     1     1    15             26.74520          74.15029
#> 16:  2060s  2001     1     1    16             26.74520          74.15029
#> 17:  2060s  2001     1     1    17             26.54335          76.39727
#> 18:  2060s  2001     1     1    18             26.34150          78.64425
#> 19:  2060s  2001     1     1    19             26.03873          80.89123
#> 20:  2060s  2001     1     1    20             25.63503          84.26170
#> 21:  2060s  2001     1     1    21             25.23132          87.63216
#> 22:  2060s  2001     1     1    22             24.82762          91.00263
#> 23:  2060s  2001     1     1    23             24.52485          94.37310
#> 24:  2060s  2001     1     1    24             24.22207          96.62008
#>     period  year month   day  hour dry_bulb_temperature relative_humidity
#>     <char> <int> <int> <int> <int>                <num>             <num>
#>     wind_speed
#>          <num>
#>  1:  1.0653853
#>  2:  1.1506162
#>  3:  1.2358470
#>  4:  1.3210778
#>  5:  1.3636932
#>  6:  1.4063087
#>  7:  1.4063087
#>  8:  1.4063087
#>  9:  1.3636932
#> 10:  1.3210778
#> 11:  1.2358470
#> 12:  1.1506162
#> 13:  1.0653853
#> 14:  0.9801545
#> 15:  0.8949237
#> 16:  0.8096929
#> 17:  0.7670774
#> 18:  0.7244620
#> 19:  0.7244620
#> 20:  0.7244620
#> 21:  0.7670774
#> 22:  0.8096929
#> 23:  0.8949237
#> 24:  0.9801545
#>     wind_speed
#>          <num>

Write EPW Files

shift_epw() writes EnergyPlus Weather files from the morphed hourly results. It returns a ShiftOutputs stage. The first chunk assigns the result while hiding verbose writer output; the second prints the stage object.

For the lower-level write path and output registry, see EpwMorpher.

epws <- shift_epw(morphed)
epws
#> <epwshiftr::ShiftOutputs>
#>   stage:  outputs
#>   status: written
#>   store:  <tempdir>/epwshiftr-future-epw-workflow/singapore-store
#>   outputs: 1
#>   ids:    query_id, plan_id, summary_id, baseline_id, morph_id

shift_outputs() lists the EPW files written by shift_epw(). These are the files you can pass to EnergyPlus or open with eplusr::read_epw().

outputs <- shift_outputs(epws)
outputs[, .(path, source_id, experiment_id, variant_label, period)]
#>                                                                                                                                     path
#>                                                                                                                                   <char>
#> 1: outputs/future-epw/MPI-ESM1-2-LR/ssp585/r1i1p1f1/2060s/ae36a1702acd-SGP_Singapore.486980_IWEC.MPI-ESM1-2-LR.ssp585.r1i1p1f1.2060s.epw
#>        source_id experiment_id variant_label period
#>           <char>        <char>        <char> <char>
#> 1: MPI-ESM1-2-LR        ssp585      r1i1p1f1  2060s

shift_data(epws) reads the written EPW file back and returns its hourly weather data with output metadata attached. This is useful for confirming that the final file contains the same kind of hourly weather values you inspected in the store-native morphed Parquet step. Output metadata such as output_id, case_id, and path are available in shift_data(epws); they are omitted here so the weather values stay visible.

epw_data <- shift_data(
    epws,
    n = 24L,
    columns = c(
        "period", "year", "month", "day", "hour",
        "dry_bulb_temperature", "relative_humidity", "wind_speed"
    )
)

epw_data
#>     period  year month   day  hour dry_bulb_temperature relative_humidity
#>     <char> <int> <int> <int> <int>                <num>             <num>
#>  1:  2060s  2001     1     1     1                 23.9                98
#>  2:  2060s  2001     1     1     2                 23.8               100
#>  3:  2060s  2001     1     1     3                 23.7               100
#>  4:  2060s  2001     1     1     4                 23.8               100
#>  5:  2060s  2001     1     1     5                 23.9                98
#>  6:  2060s  2001     1     1     6                 24.2                96
#>  7:  2060s  2001     1     1     7                 24.5                94
#>  8:  2060s  2001     1     1     8                 24.8                91
#>  9:  2060s  2001     1     1     9                 25.2                87
#> 10:  2060s  2001     1     1    10                 25.6                84
#> 11:  2060s  2001     1     1    11                 26.0                80
#> 12:  2060s  2001     1     1    12                 26.3                78
#> 13:  2060s  2001     1     1    13                 26.5                76
#> 14:  2060s  2001     1     1    14                 26.7                74
#> 15:  2060s  2001     1     1    15                 26.7                74
#> 16:  2060s  2001     1     1    16                 26.7                74
#> 17:  2060s  2001     1     1    17                 26.5                76
#> 18:  2060s  2001     1     1    18                 26.3                78
#> 19:  2060s  2001     1     1    19                 26.0                80
#> 20:  2060s  2001     1     1    20                 25.6                84
#> 21:  2060s  2001     1     1    21                 25.2                87
#> 22:  2060s  2001     1     1    22                 24.8                91
#> 23:  2060s  2001     1     1    23                 24.5                94
#> 24:  2060s  2001     1     1    24                 24.2                96
#>     period  year month   day  hour dry_bulb_temperature relative_humidity
#>     <char> <int> <int> <int> <int>                <num>             <num>
#>     wind_speed
#>          <num>
#>  1:        1.1
#>  2:        1.2
#>  3:        1.2
#>  4:        1.3
#>  5:        1.4
#>  6:        1.4
#>  7:        1.4
#>  8:        1.4
#>  9:        1.4
#> 10:        1.3
#> 11:        1.2
#> 12:        1.2
#> 13:        1.1
#> 14:        1.0
#> 15:        0.9
#> 16:        0.8
#> 17:        0.8
#> 18:        0.7
#> 19:        0.7
#> 20:        0.7
#> 21:        0.8
#> 22:        0.8
#> 23:        0.9
#> 24:        1.0
#>     wind_speed
#>          <num>

Validate and Reuse the Result

At this point the workflow has produced EPW files, but there are still a few checks worth doing before using them in EnergyPlus or passing them to someone else. These checks answer three practical questions:

  • Did every stage finish?
  • If something failed or looks incomplete, where should you look first?
  • Where are the reusable files and store artifacts?

Check Stage Health

Use shift_status() when you want a compact stage-level check. It returns a single status string so it can be used in scripts, reports, or simple guards. For a successful run, the sequence should end with an EPW stage marked written.

data.table::data.table(
    stage = c("request", "collect", "extract", "reference", "morph", "epw"),
    status = c(
        shift_status(request),
        shift_status(files),
        shift_status(extracted),
        shift_status(reference),
        shift_status(morphed),
        shift_status(epws)
    )
)
#>      stage    status
#>     <char>    <char>
#> 1: request       new
#> 2: collect collected
#> 3: extract extracted
#> 4: reference extracted
#> 5:   morph   morphed
#> 6:     epw   written

Read Diagnostics When Something Looks Wrong

Diagnostics are the first place to look when a stage is blocked, failed, or returns fewer outputs than expected. An empty diagnostics table is the normal successful result. Non-empty rows are intended to explain the stage, severity, and action rather than expose internal manifest IDs first.

For common causes and the first place to look for each class of failure, see ESGF troubleshooting.

shift_diagnostics(epws)
#> Empty data.table (0 rows and 16 cols): stage,severity,code,message,query_id,session_id...

Confirm Extraction Coverage

The final EPW depends on the extracted climate table. Even after the EPW file is written, it is useful to confirm that each morphing variable has complete monthly coverage for the requested period. Missing or incomplete rows here usually mean the original ESGF query, Dataset selection, or extraction period needs to be adjusted.

Coverage problems usually originate in query selection, time filtering, or remote access. The ESGF troubleshooting article collects those checks in one place.

coverage <- shift_coverage(epws)
coverage[, .(variable_id, complete, status, output_rows, output_file_count)]
#>    variable_id complete status output_rows output_file_count
#>         <char>   <lgcl> <char>       <int>             <int>
#> 1:        rlds     TRUE   done          12                 1
#> 2:        rsds     TRUE   done          12                 1
#> 3:         psl     TRUE   done          12                 1
#> 4:         tas     TRUE   done          12                 1
#> 5:         clt     TRUE   done          12                 1
#> 6:     sfcWind     TRUE   done          12                 1
#> 7:        hurs     TRUE   done          12                 1

Locate Reusable Files

shift_outputs() lists the written EPW files and their case metadata. These are the files to pass to EnergyPlus, archive with a simulation run, or reopen with eplusr::read_epw(). The store also keeps the intermediate Parquet artifacts so the workflow can be inspected or reused without repeating the remote query.

outputs <- shift_outputs(epws)
outputs[, .(
    file = basename(path),
    source_id,
    experiment_id,
    variant_label,
    period
)]
#>                                                                              file
#>                                                                            <char>
#> 1: ae36a1702acd-SGP_Singapore.486980_IWEC.MPI-ESM1-2-LR.ssp585.r1i1p1f1.2060s.epw
#>        source_id experiment_id variant_label period
#>           <char>        <char>        <char> <char>
#> 1: MPI-ESM1-2-LR        ssp585      r1i1p1f1  2060s

Advanced: Manifest IDs

Ordinary workflows do not need manifest IDs. They are kept available for advanced users who want to inspect the lower-level EsgStore, EpwMorpher, or manifest tables directly.

names(shift_ids(epws))
#> [1] "query_id"    "plan_id"     "summary_id"  "baseline_id" "morph_id"