Update app.py

app.py

@@ -98,6 +98,7 @@ def fetch_and_process_sdo_data(target_dt, forecast_horizon_minutes):
     all_times = sorted(list(set(input_times + [target_time])))
 
     data_maps = {}
+    last_successful_map = {}
     total_downloads = len(all_times) * len(SDO_CHANNELS)
     downloads_done = 0
     yield f"Starting download of {total_downloads} data files..."
@@ -108,18 +109,26 @@ def fetch_and_process_sdo_data(target_dt, forecast_horizon_minutes):
             yield f"Downloading [{downloads_done}/{total_downloads}]: {channel} for {t.strftime('%Y-%m-%d %H:%M')}..."
             
             if channel in ["hmi_by", "hmi_bz"]: 
-                if data_maps[t].get("hmi_bx"): data_maps[t][channel] = data_maps[t]["hmi_bx"]
+                if data_maps[t].get("hmi_bx"):
+                    smap = data_maps[t]["hmi_bx"]
+                    data_maps[t][channel] = smap
+                    last_successful_map[channel] = smap
                 continue
             
-            # *** FIX: Removed the non-existent 'a.Time.nearest' attribute. ***
             time_attr = a.Time(t - datetime.timedelta(minutes=5), t + datetime.timedelta(minutes=5))
             instrument = a.Instrument.hmi if "hmi" in channel else a.Instrument.aia
             query = Fido.search(time_attr, instrument, physobs, sample)
             
-            if not query: raise ValueError(f"No data found for {channel} near {t}. Try a slightly different time.")
-            # We fetch the first result, which is the closest match within the window.
-            files = Fido.fetch(query[0,0], path="./data/sdo_cache")
-            data_maps[t][channel] = sunpy.map.Map(files[0])
+            if query:
+                files = Fido.fetch(query[0,0], path="./data/sdo_cache")
+                smap = sunpy.map.Map(files[0])
+                data_maps[t][channel] = smap
+                last_successful_map[channel] = smap
+            elif channel in last_successful_map:
+                yield f"⚠️ WARNING: No data for {channel} near {t}. Reusing previous image."
+                data_maps[t][channel] = last_successful_map[channel]
+            else:
+                raise ValueError(f"CRITICAL: No data found for initial image of {channel}. Cannot proceed.")
             
     yield "✅ All files downloaded. Starting preprocessing..."
     output_wcs = WCS(naxis=2)
@@ -254,11 +263,9 @@ with gr.Blocks(theme=gr.themes.Soft()) as demo:
         """
         <div align='center'>
         # ☀️ Surya: Live Forecast Demo ☀️
-        ### Generate a real forecast for any recent date using NASA's Heliophysics Model.
-        **Instructions:**
-        1. Pick a date and time (at least 3 hours in the past).
-        2. Click 'Generate Forecast'. **This will be slow (5-15 minutes) as it downloads live data.**
-        3. Once complete, select different channels to explore the multi-spectrum forecast.
+        ### A Foundation Model for Solar Dynamics
+        This demo runs NASA's **Surya**, a foundation model trained to understand the physics of the Sun.
+        It looks at the Sun in 13 different channels (8 from the AIA instrument, 5 from HMI) simultaneously to learn the complex relationships between solar phenomena like coronal loops, magnetic fields, and solar flares. By seeing these interconnected views, it can generate a holistic forecast of what the entire solar disk will look like in the near future.
         </div>
         """
     )