Add fallback strategies for opening zarr stores

- Try consolidated=True first
- Fall back to consolidated=False
- Fall back to default xarray behavior
- Better error handling with detailed logging

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

app.py

@@ -61,9 +61,25 @@ def load_dataset(dataset_name, use_cache=True):
         url = CATALOG[dataset_name]["url"]
         logger.info(f"Opening zarr store at: {url}")
 
-        # Try opening with zarr_version=2 for compatibility
-        ds = xr.open_zarr(url, zarr_version=2, consolidated=True)
-        logger.info(f"Successfully opened zarr store")
+        # Try different approaches to open the zarr store
+        try:
+            # First try: zarr v2 with consolidated metadata
+            logger.info("Trying zarr_version=2 with consolidated=True")
+            ds = xr.open_zarr(url, zarr_version=2, consolidated=True)
+            logger.info(f"Successfully opened zarr store with consolidated metadata")
+        except Exception as e1:
+            logger.warning(f"Failed with consolidated=True: {e1}")
+            try:
+                # Second try: zarr v2 without consolidated metadata
+                logger.info("Trying zarr_version=2 with consolidated=False")
+                ds = xr.open_zarr(url, zarr_version=2, consolidated=False)
+                logger.info(f"Successfully opened zarr store without consolidated metadata")
+            except Exception as e2:
+                logger.warning(f"Failed with consolidated=False: {e2}")
+                # Third try: default xarray behavior
+                logger.info("Trying default xarray open_zarr")
+                ds = xr.open_zarr(url)
+                logger.info(f"Successfully opened zarr store with default settings")
         logger.info(f"Dataset dimensions: {dict(ds.dims)}")
         logger.info(f"Dataset variables: {list(ds.data_vars)}")
         logger.info(f"Dataset coordinates: {list(ds.coords)}")