|
| 1 | +#!/usr/bin/env python3 |
| 2 | +"""Demo of calculating global average sea surface temperature (SST) with SQL. |
| 3 | +
|
| 4 | +Please run the following to set up cloud resources: |
| 5 | +``` |
| 6 | +gcloud auth application-default login |
| 7 | +coiled setup |
| 8 | +``` |
| 9 | +""" |
| 10 | +import argparse |
| 11 | +import xarray as xr |
| 12 | +import xarray_sql as qr |
| 13 | + |
| 14 | +parser = argparse.ArgumentParser() |
| 15 | +parser.add_argument('--start', type=str, default='2020-01-01', help='start time ISO string') |
| 16 | +parser.add_argument('--end', type=str, default='2020-01-02', help='end time ISO string') |
| 17 | +parser.add_argument('--cluster', action='store_true', help='deploy on coiled cluster') |
| 18 | + |
| 19 | +args = parser.parse_args() |
| 20 | + |
| 21 | +if args.cluster: |
| 22 | + from coiled import Cluster |
| 23 | + |
| 24 | + cluster = Cluster( |
| 25 | + region='us-central1', |
| 26 | + worker_memory='16 GiB', |
| 27 | + spot_policy='spot_with_fallback', |
| 28 | + arm=True, |
| 29 | + ) |
| 30 | + client = cluster.get_client() |
| 31 | + cluster.adapt(minimum=1, maximum=100) |
| 32 | +else: |
| 33 | + from dask.distributed import LocalCluster |
| 34 | + cluster = LocalCluster(processes=False) |
| 35 | + client = cluster.get_client() |
| 36 | + |
| 37 | +era5_ds = xr.open_zarr( |
| 38 | + 'gs://gcp-public-data-arco-era5/ar/' |
| 39 | + '1959-2022-full_37-1h-0p25deg-chunk-1.zarr-v2', |
| 40 | + chunks={'time': 240, 'level': 1} |
| 41 | +) |
| 42 | +print('dataset opened.') |
| 43 | +era5_sst_ds = era5_ds[['sea_surface_temperature']].sel( |
| 44 | + time=slice(args.start, args.end), |
| 45 | + level=1000, # surface level only. |
| 46 | +) |
| 47 | + |
| 48 | +c = qr.Context() |
| 49 | +# chunk sizes determined from VM memory limit of 16 GiB. |
| 50 | +c.create_table('era5', era5_sst_ds, chunks=dict(time=24)) |
| 51 | + |
| 52 | +print('beginning query.') |
| 53 | +df = c.sql(""" |
| 54 | +SELECT |
| 55 | + DATE("time") as date, |
| 56 | + AVG("sea_surface_temperature") as daily_avg_sst |
| 57 | +FROM |
| 58 | + "era5" |
| 59 | +GROUP BY |
| 60 | + DATE("time") |
| 61 | +""") |
| 62 | + |
| 63 | +df.to_csv(f'global_avg_sst_{args.start}-{args.end}_*.cvs') |
0 commit comments