## 5 Personal Perspectives  
Without field measurement experiences, the authors initially believed that a full-scale/model test comparison would be the most reliable approach to validate the traditional ABL wind tunnel test, and it was assumed that the majority, if not all, of the researchers who had not actually made full-scale measurements would endorse this contention. In view of the literature disseminated to those in the profession, Refs. [8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 41, 42, 43, 44, 45, 46, 47, 51, 52, 53, 54, 55, 56, 57, 58, 59] also directly or indirectly sustain this contention. The full-scale measurement campaign for wind pressures on the Peng-cheng cooling tower (see Section 3.5) was undertaken by the authors from 2009 to 2015; after completing the on-location practice, we have some different viewpoints. [PERSON] thought that full-scale measurements were inherently less accurate and deterministic than the wind tunnel experiments they were supposed to validate, so full-scale/model test comparisons have their limitations [4]. In fact, [PERSON]'s concerns regarding the inherent inaccuracies in full-scale measurements have not been dismissed by most full-scale measurement campaigns, although the real situations were usually not truthfully reported in the literature. For example, many full-scale pressure measurements were fatally compromised by the impossibility of obtaining reliable static pressure at a point that was situated close enough to the test building, but far enough away from neighboring obstructions, and providing a reliable backing pressure. The data from the BRE Aylesbury experiment (see Section 3.1.1) showed static pressure offsets on the different backing-pressure branches due to leaks through faulty pressure transducers. It was also extremely difficult to obtain a reliable dynamic pressure reference. In addition, the pressure and load transducers used in some field studies were notorious for their zero and calibration drift. In the Peng-cheng cooling tower full-scale measurements, we directly arranged individual pressure transducers on the tower's external surface, instead of using pressure taps connected with pressure transducers via the tubing, to avoid the faulty pressure transducer's contamination of the whole measurement system. In addition, the static reference pressure was obtained using an innovative method of calculating the value from the total wind pressure measured at a point with an invariant mean wind pressure coefficient, to address the issue that the reference static pressure traditionally established for pressure measurements on full-scale structures by using a pressure transducer arranged inside a cabin near the location cannot play the same role as static pressure in the wind tunnel [60]. Moreover, two anemometers were initially arranged near the Peng-cheng cooling tower at a height of 20 m for measuring the dynamic pressure reference, which is 110 m lower than the pressure measurement section. Therefore, the correlations between the measured wind velocity samples and the measured wind pressure samples were extremely low. To deal with this issue, wind velocity samples were extracted from the full-scale wind pressure samples measured in the quasi-steady region on the actual large cooling tower in order to calculate the dynamic pressure reference [61]. Finally, the zero-drift issue was effectively addressed by repeated and timely calibrations of the transducers when on location. However, even with these well-designed and correctly implemented field measurement practices, the data measured at the Peng-cheng cooling tower are still less deterministic and usually cannot clearly show any rule of physics. We suggest that this is associated with the non-stationarity and the non-uniformity of the realistic wind velocity field and the constantly changing wind direction at the location, which are hard to control.