The NASA/NGA Shuttle Radar Topography Mission (SRTM) collected interferometric radar data which has been used by the Jet Propulsion Laboratory to generate a near-global topography data product for latitudes smaller than 60°. One of the primary goals of the mission was to produce a data set that was globally consistent and with quantified errors. To achieve this goal, an extensive global ground campaign was conducted by NGA and NASA to collect ground truth that would allow for the global validation of this unique data set. This paper documents the results of this SRTM validation effort using this global data set. The table shown below summarizes our results (all quantities represent 90 percent errors in meters).In the paper, we present a detailed description of how the results in this table were obtained. We also present detailed characterizations of the height and planimetric components of the error, their magnitudes, geographical distribution, and spatial structure.

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We conduct the first broad-based international study on bank-level failures covering 92 countries over 2000–2014, investigating national cultural variables as failure determinants. We find individualism and masculinity are positively associated with bank failure, but they operate through different channels. Managers in individualist countries assume more portfolio risk, while governments in masculine countries allow banks to operate with less liquidity and less often bail out troubled institutions. Findings are robust to accounting for endogeneity, different techniques and measures, and additional controls. Results have implications for prudential policies, including regulation, supervision, and bailout strategies, that may partially mitigate some negative effects of culture.

The TOPEX/POSEIDON altimeter measurement system is evaluated for the first 46 repeat cycles (September 23, 1992–December 23, 1993) using tracks over the Great Lakes. The temporal variations in lake level are removed from the altimeter measurements using in situ lake level measurements, thus permitting the performance of the altimeter system to be assessed. For the NASA altimeter, the root‐mean‐square (RMS) scatter of the residuals is 3.95 cm using all the tracks over the lakes. However, some of the scatter in this result is probably due to lake tides or seiche, which can amount to a few centimeters amplitude near the ends of the lakes. When the seven best tracks are used, which cross the center of the lakes where tides/seiche effects are minimal, the RMS error is reduced to either 2.9 or 3.0 cm, depending on whether the Centre National d'Etudes Spatiales (CNES) or NASA orbit is used. This places an upper limit on the error budget of the altimeter system, excluding ocean tides and inverse barometer effect. There are several short‐period variations in the residuals. The most pronounced is a 55‐day period, with a 1‐cm amplitude, which we believe is (at least in part) due to orbit error. When the model‐derived wet tropospheric correction is substituted for the TOPEX microwave radiometer correction, the RMS error increases significantly, possibly resulting in an annual cycle of a few centimeters. Evaluation of the ionospheric correction indicates that the dual‐frequency correction provides an average improvement of 0.85 cm over the Doppler orbitography and radiopositioning integrated by satellite (DORIS) correction. Although there are insufficient data to directly assess the CNES altimeter, the relative bias between the altimeters is estimated to be either −14.3 or −15.6 cm (NASA altimeter measuring short), depending on whether the DORIS or dual‐frequency ionospheric correction is applied to the NASA altimeter.

We present estimates for the mean bias of the TOPEX/POSEIDON NASA altimeter (ALT) and the Centre National d'Etudes Spatiales altimeter (SSALT) using in situ data gathered at Platform Harvest during the first 36 cycles of the mission. Data for 21 overflights of the ALT and six overflights of the SSALT have been analyzed. The analysis includes an independent assessment of in situ measurements of sea level, the radial component of the orbit, wet tropospheric path delay, and ionospheric path delay. (The sign convention used in this paper is such that, to correct the geophysical data record values for sea level, add the bias algebraically. Unless otherwise stated, the uncertainty in a given parameter is depicted by ±σx, where σx is the sample standard deviation of x about the mean.) Tide gauges at Harvest provide estimates of sea level with an uncertainty of ±1.5 cm. The uncertainty in the radial component of the orbit is estimated to be ±1.3 cm. In situ measurements of tropospheric path delay at Harvest compare to within ±1.3 cm of the TOPEX/POSEIDON microwave radiometer, and in situ measurements of the ionospheric path delay compare to within −0.4±0.7 cm of the dual‐frequency ALT and 1.1±0.6 cm of Doppler orbitography and radiopositioning integrated by satellite. We obtain mean bias estimates of −14.5±2.9 cm for the ALT and +0.9±3.1 cm for the SSALT (where the uncertainties are based on the standard deviation of the estimated mean σx–/y , which is derived from sample statistics and estimates for errors that cannot be observed). These results are consistent with independent estimates for the relative bias between the two altimeters. A linear regression applied to the complete set of data shows that there is a discernable secular trend in the time series for the ALT bias estimates. A preliminary analysis of data obtained through cycle 48 suggests that the apparent secular drift may be the result of a poorly sampled annual signal.