Attempts to improve the urban component in meteorology and numerical weather prediction models in recent years have been hampered by a paucity of meteorological data in the urban boundary layer (UBL), especially in the region above, but close to, building height. This region is precisely where local energy balances and drag combine with prevailing synoptic patterns to transmit fluid dynamical information up and down spatial scales, with implications for (i) urban weather prediction, (ii) event forecasting (e.g. heatwaves, climatic conditions during sporting events, releases of hazardous substances), and (iii) sustainable urban planning for high density liveable cities. However, capturing meteorological data in urban areas above the mean roof height is problematic using conventional techniques.

The BBUBL project proposed Biotelemetry/bio-aerial-platforms as a novel and practicable solution to the data paucity above urban rooftops in the UBL, and to circumvent the regulatory issues related to use of unmanned aerial systems. The project developed a suite of low-cost Avian-Meteorology-Instrument Packages (AvMIPs) for ensemble deployment in Birmingham as a suitably large and heterogeneous test case.

The AvMIPs were tested rigorously to determine: (i) data biases and reliability; (ii) sensor response to temperature variations; (iii) effect of radiation; and (iv) effect of bird's body temperature and other 'platform effects'. After quality assurance and control of the packages had been determined to be adequate, the primary targets of the AvMIP deployment were the thermal and moisture structures of the UBL at the city and neighbourhood scales. Favourable weather conditions for deployment will be identified via pre-deployment modelling using a mesoscale meteorological model (WRF, Weather Research and Forecasting).

Subsequent analysis and interpretation of the AvMIP data and synthesis of the data together with Birmingham's canyon (3m) meteorological data were assisted by post-deployment modelling for the measurement periods.

Overall, this project aimed to deliver a novel, and rigorously tested, technology for probing the UBL. A unique dataset for the UBL of a major European conurbation was obtained, elucidating climate mitigation issues such as the cooling (or heating) capability/capacity of a large park (or a city centre) to a city's UBL, and scientific issues such as the magnitude of the 'blending height' at which the effect of urban surface heterogeneity is no longer detectable.

Success of the project was seen as a necessary step towards deployment of chemical sensors, and lead to generation of unprecedented datasets of the urban atmosphere for both research and city-planning purposes. Novel field deployments of the kind proposed by the project require strong partnerships with a wide variety of stakeholders. The Royal Pigeon Racing Association (RPRA) provide critical support in terms of birds that will behave in well determined ways. The RPRA have experience of mounting payloads on pigeons and so can ensure that payloads are appropriately in size, weight, etc., and that pigeon deployments delivered the data sought. Birmingham City Council supported the project in three ways: 1. As one of the principal end-users of the results (feeding into improved diagnosis and forecasting of urban climatology across the city through the joint city-university BUCCANEER project); 2. In order to facilitate use of birds in open urban spaces such as parks; and 3. In order to facilitate access to city buildings on which gulls are nesting. Dr Stefan Bodnar, an ecological consultant, supported the project by acting as principal bird handler and as a consultant for public dissemination of our work.

Objectives

To directly address the data sparsity of meteorological measurements in the urban boundary layer (UBL), especially in the region above, but close to, building height, and to circumvent the regulatory issues related to use of Unmanned Aerial Systems, the project proposed developing and deploying instrument payloads on birds.

The project set out the following research questions, to be addressed by a series of objectives. RESEARCH QUESTIONS:
(1) Can biotelemetry/bio-aerial-platforms be used to deliver observations of temperature, humidity and wind speed in the UBL with accuracy and precision sufficient for research?
(2) Can the data derived from biotelemetry/bioaerial-platforms be used to inform the structure of the UBL at the city scale and the local IBLs at neighbourhood scales?
(3) If so, what is the cooling (or heating) capability/capacity of a large park (or a city centre) to a city's UBL and what is the magnitude of the blending height?
(4) How do such measurements compare to results derived from a numerical weather prediction (NWP) model?
(5) What lessons can be learnt to assess the feasibility of other payloads (e.g. chemical sensors)?

OBJECTIVES were:
a) To develop a suite of low-cost Avian-Meteorology-Instrument Packages (AvMIPs) (i) capable of sensing temperature (changes of at least 0.2 degree with a 1 sec response time) and humidity (changes of 5% with a 15 sec response time) and (ii) suitable for a range of bird taxa (raptors, pigeons, and gulls [Larus spp.]), with increasing deployment duration from mins to hours to days, respectively.
b) To test AvMIPs rigorously in the following aspects: (i) data biases and reliability; (ii) responses to temperature variations; (iii) effect of radiation; and (iv) effect of bird's body temperature.
c) To conduct pre-deployment modelling using a NWP model. This will be used to design a deployment plan. The robustness of this approach will ensure scales of interest (city and neighbourhood scales only), time of day (mainly daytime and early morning), and seasonality (both summer and winter) are all taken into account.
d) To execute the deployment plan derived from c) in Birmingham for the favourable synoptic weather conditions for the ensemble AvMIP deployment. Post-deployment modelling will also be completed.
e) To synthesise and analyse the AvMIP and BUCL data along with post-deployment modelling output, to identify the feasibility, reliability, applicability and benefits of the AvMIPs as an observational platform. Results from this analysis will be used to make recommendations and to scope the design of future biotelemetry/bio-aerial-platform payloads and deployment strategies.