diff --git a/wetb/wind/dir_mapping.py b/wetb/wind/dir_mapping.py
index 4da160f48e346cfece5717bfdad19599ae81069d..b2e6afe15af48c0b2da42cf50095e8f56b2ae5f5 100644
--- a/wetb/wind/dir_mapping.py
+++ b/wetb/wind/dir_mapping.py
@@ -105,12 +105,16 @@ def xyz2uvw(x, y, z, left_handed=True):
         y *= -1
     theta = deg(np.arctan2(np.mean(y), np.mean(x)))
     SV = cosd(theta) * y - sind(theta) * x
-    SUW = cosd(theta) * x + sind(theta) * y
 
-    #% rotation around y of tilt
-    tilt = deg(np.arctan2(np.mean(z), np.mean(SUW)))
-    SU = SUW * cosd(tilt) + z * sind(tilt);
-    SW = z * cosd(tilt) - SUW * sind(tilt);
+#     SUW = cosd(theta) * x + sind(theta) * y
+# 
+#     #% rotation around y of tilt
+#     tilt = deg(np.arctan2(np.mean(z), np.mean(SUW)))
+#     SU = SUW * cosd(tilt) + z * sind(tilt);
+#     SW = z * cosd(tilt) - SUW * sind(tilt);
+
+    SU = cosd(theta) * x + sind(theta) * y
+    SW = z
 
     return np.array([SU, SV, SW])
 
@@ -212,3 +216,5 @@ def abvrel2xyz(alpha, beta, vrel):
     z[m] = sign_vsz[m] * np.sqrt(vrel[m] ** 2 / ((1 / np.tan(beta[m])) ** 2 + 1 + (np.tan(alpha[m]) / np.tan(beta[m])) ** 2))
 
     return np.array([x, y, z]).T
+
+
diff --git a/wetb/wind/tests/test_mann_parameters.py b/wetb/wind/tests/test_mann_parameters.py
index 8565607ffa2825129777102b7c943deaf2840d38..0b3f883620a53e583460e85d6d4e8777d7368ec2 100644
--- a/wetb/wind/tests/test_mann_parameters.py
+++ b/wetb/wind/tests/test_mann_parameters.py
@@ -8,7 +8,7 @@ from wetb import gtsdf
 from wetb.wind.dir_mapping import wsp_dir2uv
 from wetb.wind.turbulence.mann_parameters import fit_mann_model_spectra
 import numpy as np
-from wetb.wind.turbulence.turbulence_spectra import spectra
+from wetb.wind.turbulence.spectra import spectra
 import os
 tfp = os.path.join(os.path.dirname(__file__), "test_files/") + "/"
 
diff --git a/wetb/wind/turbulence/mann_parameters.py b/wetb/wind/turbulence/mann_parameters.py
index b0a94bc7c9dfa87895e986769c1f45013c030642..9a411fbb26ca4bd21fdfd623761cdb20e6fa6cd7 100644
--- a/wetb/wind/turbulence/mann_parameters.py
+++ b/wetb/wind/turbulence/mann_parameters.py
@@ -10,7 +10,7 @@ import os
 from scipy.interpolate import RectBivariateSpline
 
 import numpy as np
-from wetb.wind.turbulence.turbulence_spectra import spectra, logbin_spectra, \
+from wetb.wind.turbulence.spectra import spectra, logbin_spectra, \
     plot_spectrum
 
 
@@ -151,8 +151,8 @@ def fit_mann_model_spectra(k1, uu, vv=None, ww=None, uw=None, log10_bin_size=.2,
         _plot_spectra(k1, uu, vv, ww, uw, plt=plt)
         plot_mann_spectra(*x, plt=plt)
         plt.title('ae:%.3f, L:%.1f, G:%.2f' % tuple(x))
-        plt.xlabel = ('Wavenumber, k1 [m$^{-1}$]')
-        plt.xlabel = ('Spectral density, $k_1F(k1) [m^2/s^2]$')
+        plt.xlabel('Wavenumber $k_{1}$ [$m^{-1}$]')
+        plt.ylabel(r'Spectral density $k_{1} F(k_{1})/U^{2} [m^2/s^2]$')
         plt.legend()
         plt.show()
     return x
@@ -248,8 +248,8 @@ def fit_ae(sf, u, L, G, min_bin_count=None, plt=False):
         muu = get_mann_model_spectra(ae, L, G, k1)[0]
         plt.semilogx(k1, k1 * muu, 'g', label='ae:%.3f, L:%.1f, G:%.2f' % (ae, L, G))
         plt.legend()
-        plt.xlabel = ('Wavenumber, k1 [m$^{-1}$]')
-        plt.xlabel = ('Spectral density, $k_1F(k1) [m^2/s^2]$')
+        plt.xlabel('Wavenumber $k_{1}$ [$m^{-1}$]')
+        plt.ylabel(r'Spectral density $k_{1} F(k_{1})/U^{2} [m^2/s^2]$')
         plt.show()
     return ae
 
@@ -267,6 +267,8 @@ def _plot_spectra(k1, uu, vv=None, ww=None, uw=None, mean_u=1, log10_bin_size=.2
     def plot(xx, label, color, plt):
         plt.semilogx(bk1, bk1 * xx * 10 ** 0 / mean_u ** 2 , '.' + color, label=label)
     plot(buu, 'uu', 'r', plt)
+    plt.xlabel('Wavenumber $k_{1}$ [$m^{-1}$]')
+    plt.ylabel(r'Spectral density $k_{1} F(k_{1})/U^{2} [m^2/s^2]$')
     if (bvv) is not None:
         plot(bvv, 'vv', 'g', plt)
     if bww is not None:
@@ -289,9 +291,10 @@ def plot_mann_spectra(ae, L, G, style='-', u_ref=1, plt=None, spectra=['uu', 'vv
 if __name__ == "__main__":
     from wetb import gtsdf
     from wetb.wind.dir_mapping import wsp_dir2uv
-    
-    """Example of fitting Mann parameters to a time series"""
     from wetb import wind
+    import matplotlib.pyplot as plt
+
+    """Example of fitting Mann parameters to a time series"""
     ds = gtsdf.Dataset(os.path.dirname(wind.__file__)+"/tests/test_files/WspDataset.hdf5")#'unit_test/test_files/wspdataset.hdf5')
     f = 35
     u, v = wsp_dir2uv(ds.Vhub_85m, ds.Dir_hub_)
@@ -300,7 +303,6 @@ if __name__ == "__main__":
     u -= u_ref
 
     sf = f / u_ref
-    import matplotlib.pyplot as plt
     ae, L, G = fit_mann_model_spectra(*spectra(sf, u, v), plt = plt)
     print (ae, L, G)
 
diff --git a/wetb/wind/turbulence/turbulence_spectra.py b/wetb/wind/turbulence/spectra.py
similarity index 97%
rename from wetb/wind/turbulence/turbulence_spectra.py
rename to wetb/wind/turbulence/spectra.py
index 5dc626e3303d9a31c7e88d97021ced7e639a7b39..40aa0ac3f0d3db47521098ebd2f0825adcae6051 100644
--- a/wetb/wind/turbulence/turbulence_spectra.py
+++ b/wetb/wind/turbulence/spectra.py
@@ -87,6 +87,10 @@ def spectra(spacial_frq, u, v=None, w=None, detrend=True):
     if np.mean(u) > 1:
         k /= np.mean(u)
         u = u - np.mean(u, 0)
+    if v is not None:
+        v = v - np.mean(v, 0)
+    if w is not None:
+        w = w - np.mean(w, 0)
     if detrend:
         u, v, w = detrend_wsp(u, v, w)