SatHDSS · satellite algae data explorer
Which satellite sees algae, where, and how often
Three icddr,b surveillance sites in Bangladesh form a coastal → riverine → urban inland gradient. The classic ocean-colour cholera mechanism should weaken along it while local eutrophic blooms take over. This site is the data layer behind that test: every source, variable, method, script and paper, cross-linked.
26
Algae datasets
25 free · 14 need no account
10
Algae variables
formula, lag and panel column for each
12
Papers
4 cited but missing from the folder
The three sites
Rural COASTAL
Chakaria HDSS
21.78940 N, 92.05500 E ·
22.9 x 29.4 km · 10 km to the sea
- Algae regime
- THE KEY SITE. Coastal ocean-colour chlorophyll from the Bay of Bengal IS directly applicable here. Brackish shrimp ponds sit in exactly the salinity band optimal f…
- Datasets that apply
- 16 yes 8 partial 2 no
Rural riverine
Matlab HDSS
23.39130 N, 90.70120 E ·
20.4 x 22.1 km · 250 km to the sea
- Algae regime
- MIXED. The Meghna is wide enough for 250-300 m sensors, so both the regional river-plume signal and local pond blooms are observable.
- Datasets that apply
- 11 yes 11 partial 4 no
Urban inland
Dhaka City
23.78660 N, 90.42350 E ·
17.6 x 26.0 km · 300 km to the sea
- Algae regime
- LOCAL eutrophic blooms dominate. Coastal plankton intrusion is essentially irrelevant at this distance.
- Datasets that apply
- 9 yes 6 partial 11 no
The design in one sentence. The three sites form a COASTAL -> RIVERINE -> URBAN INLAND gradient. This is the study design's greatest strength: the classic coastal-chlorophyll/plankton-intrusion hypothesis (Lobitz 2000, Jutla 2013, Constantin de Magny 2008) should be STRONGEST at Chakaria, INTERMEDIATE at Matlab, and WEAKEST at Dhaka, where local eutrophic pond and lake blooms should dominate instead. That gradient is directly testable and has never been published.
Start here
1 · See what exists
Every algae source, filtered by site, with cadence, resolution, cost, login and the exact command that fetches it.
2 · Understand the numbers
What each variable is, the formula behind it, its expected lag to cholera, and how the pipeline turns passes into panels.
Highest-reliability sources
| Code | Product | Reliability | Cadence | Resolution | Cost | |
|---|---|---|---|---|---|---|
AL01 |
ESA Ocean Colour CCI v6.0 — merged multi-sensor chlorophyll-a | A+ Gold | Daily / 5-day / 8-day / MONTHLY | 4 km (1 km regional available) | FREE | detail → |
AL02 |
Copernicus Marine GlobColour — L4 gap-free multi-sensor chlorophyll | A+ Gold | DAILY (gap-free!) | 4 km | FREE | detail → |
AL03 |
Sentinel-2 MSI Level-2A (harmonised) | A+ Gold | 5 days (2-3 d with S2C from 2025) | 10 m (B2,3,4,8) / 20 m (B5 red-edge 705 nm) | FREE | detail → |
AL04 |
Sentinel-3 OLCI — 21 bands incl. 620 nm (phycocyanin) & 709 nm (red e… | A+ Gold | ~1-2 days (S3A + S3B) | 300 m full resolution | FREE | detail → |
AL05 |
Landsat 5 / 7 / 8 / 9 Collection 2 Level-2 | A+ Gold | 16 days per satellite (~8 d with two in… | 30 m | FREE | detail → |
AL06 |
MODIS-Aqua Level-3 SMI | A Reliable | Daily / 8-day / monthly | 4.6 km | FREE | detail → |
AL07 |
SeaWiFS Level-3 SMI | A Reliable | Daily / 8-day / monthly | 9 km (4 km avail.) | FREE | detail → |
AL08 |
VIIRS SNPP / NOAA-20 chlorophyll (NOAA CoastWatch) | A Reliable | DAILY | 4 km (750 m for some SNPP products) | FREE | detail → |
One honest limit, stated up front. Everything the Earth Engine pipeline produces is an
ordinal index, not a calibrated concentration. Sen2Cor is land-optimised and returns negative
reflectance over dark turbid water. For publishable mg/m³ you need ACOLITE Dark Spectrum Fitting on
Sentinel-2 L1C, or local calibration against in-situ chlorophyll — see
Methods and dataset AL18.