diff --git a/extract_c.py b/extract_c.py
new file mode 100644
index 0000000..7dfac11
--- /dev/null
+++ b/extract_c.py
@@ -0,0 +1,27 @@
+import argparse
+import numpy as np
+import dnstool
+
+# Commandline argument parser
+parser = argparse.ArgumentParser()
+parser.add_argument("-c", "--case", help="target case name", required=True)
+args = parser.parse_args()
+params = vars(args)
+
+casename = params["case"]
+field_idx = 4
+
+cases = dnstool.case_library()
+
+case = cases[casename]
+
+nx, ny, nz = case.shape
+
+with open("c.dat", "w+") as ufile:
+
+    storage = np.memmap(ufile, dtype=np.double, shape=(nx, len(case.data_files), ny, nz))
+
+    for i, fname in enumerate(case.data_files):
+        print(i, fname)
+        time, y = case.read_single_field(fname, field_idx)
+        storage[:,i,:,:] = 1. - y.T
diff --git a/extract_u.py b/extract_u.py
new file mode 100644
index 0000000..d25f0a8
--- /dev/null
+++ b/extract_u.py
@@ -0,0 +1,27 @@
+import argparse
+import numpy as np
+import dnstool
+
+# Commandline argument parser
+parser = argparse.ArgumentParser()
+parser.add_argument("-c", "--case", help="target case name", required=True)
+args = parser.parse_args()
+params = vars(args)
+
+casename = params["case"]
+field_idx = 0
+
+cases = dnstool.case_library()
+
+case = cases[casename]
+
+nx, ny, nz = case.shape
+
+with open("u.dat", "w+") as ufile:
+
+    storage = np.memmap(ufile, dtype=np.double, shape=(nx, len(case.data_files), ny, nz))
+
+    for i, fname in enumerate(case.data_files):
+        print(i, fname)
+        time, u = case.read_single_field(fname, field_idx)
+        storage[:,i,:,:] = u.T