diff --git a/src/mintpy/tropo_pyaps3.py b/src/mintpy/tropo_pyaps3.py
index 64939eca1..b590c19e0 100644
--- a/src/mintpy/tropo_pyaps3.py
+++ b/src/mintpy/tropo_pyaps3.py
@@ -466,7 +466,22 @@ def check_pyaps_account_config(tropo_model):
 
 
 ###############################################################
+from concurrent.futures import ThreadPoolExecutor
+
+
 def dload_grib_files(grib_files, tropo_model='ERA5', snwe=None):
+    # import pdb; pdb.set_trace()
+    with ThreadPoolExecutor(max_workers=64) as worker:
+        futures = []
+        for grib_file in grib_files:
+            future = worker.submit(dload_grib_files_worker, [grib_file], tropo_model, snwe)
+            futures.append(future)
+        for future in futures:
+            future.result()
+
+    return dload_grib_files_worker(grib_files, tropo_model, snwe)
+
+def dload_grib_files_worker(grib_files, tropo_model='ERA5', snwe=None):
     """Download weather re-analysis grib files using PyAPS
     Parameters: grib_files : list of string of grib files
     Returns:    grib_files : list of string
diff --git a/src/mintpy/utils/readfile.py b/src/mintpy/utils/readfile.py
index 104057099..882c6deef 100644
--- a/src/mintpy/utils/readfile.py
+++ b/src/mintpy/utils/readfile.py
@@ -1897,7 +1897,7 @@ def read_snap_dim(fname):
     bases = ds.find("MDElem[@name='Baselines']").findall("MDElem")[0].findall("MDElem")
 
     # date12
-    dates = [x.get('name').split(':')[1].strip() for x in bases]
+    dates = [x.get('name').split('_')[1].strip() for x in bases]
     [date1, date2] = sorted(dt.datetime.strptime(x, '%d%b%Y').strftime('%Y%m%d') for x in dates)
     dim_dict['DATE12'] = f'{date1[2:]}-{date2[2:]}'