Configuration
All convert and batch convert subcommands accept a --config TOML file plus
individual flag overrides. The priority order is:
built-in default < --config file < individual CLI flags
--config may set any subset of fields; a per-field flag then overrides the
config for that field only.
NRT flags
| Flag | Field | Default |
|---|---|---|
--deph-source / --no-deph-source | has_deph_source | true for BO/GL, false for AR/MO |
--profile-coords / --no-profile-coords | has_profile_coords | true for BO, false otherwise |
--pattern <GLOB> | pattern | see the batch patterns |
DEPH is auto-detected. NRT always performs the bidirectional PRES↔DEPH conversion when the file contains a
DEPHvariable, regardless ofhas_deph_source. The flag only forces DEPH handling on for files where the variable might otherwise be skipped.
CORA flags
| Flag | Field | cora default | cora_legacy default |
|---|---|---|---|
--time-var <VAR> | time_var | TIME | JULD |
--qc-type <int|char> | qc_type | int | char |
--time-qc / --no-time-qc | has_time_qc | true | false |
--deph-source / --no-deph-source | has_deph_source | true | false |
--pattern <GLOB> | pattern | *.nc | *.nc |
TOML config format
# NRT
has_deph_source = true
has_profile_coords = false
pattern = "AR_PR_CT_*.nc" # optional
# CORA
time_var = "TIME"
qc_type = "int" # "int" or "char"
has_time_qc = true
has_deph_source = true
pattern = "*.nc" # optional
Environment variables
ctddump honours a few environment variables for operational tuning. They do
not change the contents of the output, only memory use, speed, and the
on-disk row-group layout, which is why they live in the environment rather than
as per-command flags.
| Variable | Effect | When unset |
|---|---|---|
CTDDUMP_CHUNK_ROWS | Observation rows assembled per streamed chunk (each written as one Parquet row group). Lower = less memory but more row groups; higher = more memory but fewer. Applies to convert, batch, concat, and the streaming filters (filter / dropqc / dropna / markdup / dedup). | 1000000 |
POLARS_MAX_THREADS | Size of Polars’ internal thread pool. batch / concat pin this to 1 so their own --threads is the real knob, but a value you set is respected. | pinned to 1 by batch / concat |
RUST_MIN_STACK | Worker-thread stack size, in bytes. Raised to 16 MiB for the deep call chains in Polars’ Parquet writer; a larger value you set is respected. | raised to 16 MiB |
CTDDUMP_CHUNK_ROWS is the only one most users would ever change, see
Technical notes for why streaming in chunks matters. The
helper scripts expose it directly as --chunk-rows N, which
exports it for every ctddump process they launch.