Besides new economical, managerial and social challenges associated with growing cities, the modifications caused in the energy budget of the urban surface intensifies the existing urban heat island (UHI). UHI can vary temporally and spatially according to meteorological conditions, landscape and urban typologies. Urban cover and form, as well as anthropogenic activities, pose an important effect on the city’s thermal behaviour that influence UHI and therefore the quality of life of the citizens. In this study, we focus on quantifying the air temperature spatiotemporal patterns across the urban and peri-urban area of Heraklion, Greece at a grid of 100 m x 100 m cells. We use point air temperature observations from the Wireless Sensors Network of Heraklion and interpolate spatially by means of sophisticated geostatistical modelling parameterized with satellite derived predictors. Regression kriging interpolation technique is implemented over the study area, using different predictors to minimize the uncertainty in air temperature estimation. We deal for multicollinearity between predictors and spatio-temporal correlations between measurements. A maximum magnitude of UHI ~ 4 oC has been observed between 04:00-05:00 (UTC+3). Cross-validations indicate a mean MAE ~0.86 oC in the estimated air temperature maps.
Two feasibility studies for spectrographs that can deliver at least 4000 MOS slits over a 1° field at the prime focuses of
the Anglo-Australian and Calar Alto Observatories have been completed. We describe the design and science case of the
Calar Alto eXtreme Multiplex Spectrograph (XMS) for which an extended study, half way between feasibility study and
phase-A, was made. The optical design is quite similar than in the AAO study for the Next Generation 1 degree Field
(NG1dF) but the mechanical design of XMS is quite different and much more developed. In a single night, 25000 galaxy
redshifts can be measured to z~0.7 and beyond for measuring the Baryon Acoustic Oscillation (BAO) scale and many
other science goals. This may provide a low-cost alternative to WFMOS for example and other large fibre spectrographs.
The design features four cloned spectrographs which gives a smaller total weight and length than a unique spectrograph
to makes it placable at prime focus. The clones use a transparent design including a grism in which all optics are about
the size or smaller than the clone rectangular subfield so that they can be tightly packed with little gaps between
subfields. Only low cost glasses are used; the variations in chromatic aberrations between bands are compensated by
changing a box containing the grism and two adjacent lenses. Three bands cover the 420nm to 920nm wavelength range
at 10A resolution while another cover the Calcium triplet at 3A. An optional box does imaging. We however also studied
different innovative methods for acquisition without imaging. A special mask changing mechanism was also designed to
compensate for the lack of space around the focal plane. Conceptual designs for larger projects (AAT 2º field, CFHT,
VISTA) have also been done.