From gravity rate-of-change as determined by absolute gravity measurements at 8 absolute gravity stations that are collocated with continuous GPS stations in the area, the value of (1/alpha ) is found to be (-,0.165pm 0.012) (upmu {hbox {Gal}}/{hbox {mm}}).
a Gravity rates from GRACE models (2002 2014).
Fig. 2 Gravity rates extracted from GRACE models.
Figure 1 shows the original gravity rates of GRACE and GPS-derived vertical velocities from W1315.
Meanwhile, the influence of the value of (alpha ), which represents the ratio between GIA-induced uplift rate and GIA-induced gravity-rate-of-change (before the correction for surface uplift), is more obvious in areas with high vertical uplift, but is smaller in the Nelson River basin.
Xc is the critical sludge concentration determining the limiting flux FL (total flux resulted from the gravity settling rate and applied sludge-withdrawal rate) for the underflow concentration Xu (Metcalf and Eddy 1998).
The difference in the gravity reduction rate (Ads) between g2 t) and g3 t) is (46) This rate difference is exactly derived from the evapotranspiration, because the evapotranspiration effect is included in the second term in Eq. (40) and in the first term in Eq. (41).
Terwillinger et al. (1951) showed insignificant role of maximum theoretical gravity drainage rate, and a strong dependency between ultimate recovery and production rate.
Gravity changes rate during 2009 2010 period is the biggest one.
Here, (1) where is the average gravity change rate at the i th station during 2004 2009 (2001–2009 for the reference site A1), N is the total number of observation sites, and σis the standard deviation of the linear regression against the observations at the ith station (solid lines in Figs. 3 and 4, see also column (e) of Table 1).
