diff --git a/settings.py b/settings.py
index 785576d..6c1a595 100644
--- a/settings.py
+++ b/settings.py
@@ -9,6 +9,7 @@ path_BS_raw_data = ""
 filename_BS_raw_data = ""
 BS_raw_data = np.array([])
 r = np.array([])
+r_2D = np.array([])
 freq = np.array([])
 freq_text = list()
 time = np.array([])
@@ -45,7 +46,7 @@ snr_reshape = np.array([])
 DataFrame_acoustic = pd.DataFrame()
 
 # --- Processed data in Acoustic Data Tab and used in Acoustic processing tab ---
-BS_data = np.array([])
+BS_data = np.array([])              # BS data limited with tmin and tmax values of spin box
 BS_data_section = np.array([])
 Noise_data = np.array([])
 SNR_data = np.array([])
@@ -61,6 +62,8 @@ BS_data_averaged = np.array([])
 
 # --- Sample Data ---
 
+samples = []
+
 fine_sediment_path = ""
 fine_sediment_filename = ""
 fine_sediment_columns = []
@@ -90,4 +93,31 @@ frac_vol_sand_cumul = np.array([])                  # Cumulated volume fraction
 Ctot_fine_per_cent = np.array([])
 Ctot_sand_per_cent = np.array([])
 
+# --- Acoustic inversion method ---
+
+temperature = 0
+water_attenuation = np.array([])
+water_velocity = 0
+
+X_exponent = np.array([])
+
+zeta = np.array([])
+
+kt_corrected = np.array([])
+kt_corrected_2D = np.array([])
+kt_corrected_3D = np.array([])
+J_cross_section = np.array([])
+
+frequencies_pair = np.array([])
+VBI_cross_section = np.array([])
+
+frequency_to_compute_SSC = 0
+ks = 0
+
+SSC_fine = np.array(())
+SSC_sand = np.array([])
+
+
+
+