The CLoud–Aerosol–Radiation interaction and forcing: year 2017 (CLARIFY-2017) measurement campaign

The representations of clouds, aerosols, and cloud–aerosol–radiation impacts remain some of the largest uncertainties in climate change, limiting our ability to accurately reconstruct past climate and predict future climate. The south-east Atlantic is a region where high atmospheric aerosol loadings and semi-permanent stratocumulus clouds are co-located, providing an optimum region for studying the full range of aerosol–radiation and aerosol–cloud interactions and their perturbations of the Earth’s radiation budget. While satellite measurements have provided some useful insights into aerosol–radiation and aerosol–cloud interactions over the region, these observations do not have the spatial and temporal resolution, nor the required level of precision to allow for a process-level assessment. Detailed measurements from high spatial and temporal resolution airborne atmospheric measurements in the region are very sparse, limiting their use in assessing the performance of aerosol modelling in numerical weather prediction and climate models. CLARIFY-2017 was a major consortium programme consisting of five principal UK universities with project partners from the UK Met Office and European- and USA-based universities and research centres involved in the complementary ORACLES, LASIC, and AEROCLO-sA projects. The aims of CLARIFY-2017 were fourfold: (1) to improve the representation and reduce uncertainty in model estimates of the direct, semi-direct, and indirect radiative effect of absorbing biomass burning aerosols; (2) to improve our knowledge and representation of the processes determining stratocumulus cloud microphysical and radiative properties and their transition to cumulus regimes; (3) to challenge, validate, and improve satellite retrievals of cloud and aerosol properties and their radiative impacts; (4) to improve the impacts of aerosols in weather and climate numerical models. This paper describes the modelling and measurement strategies central to the CLARIFY-2017 deployment of the FAAM BAe146 instrumented aircraft campaign, summarizes the flight objectives and flight patterns, and highlights some key results from our initial analyses

Duration of androgen deprivation therapy with postoperative radiotherapy for prostate cancer: a comparison of long-course versus short-course androgen deprivation therapy in the RADICALS-HD randomised trial

Background Previous evidence supports androgen deprivation therapy (ADT) with primary radiotherapy as initial treatment for intermediate-risk and high-risk localised prostate cancer. However, the use and optimal duration of ADT with postoperative radiotherapy after radical prostatectomy remains uncertain. Methods RADICALS-HD was a randomised controlled trial of ADT duration within the RADICALS protocol. Here, we report on the comparison of short-course versus long-course ADT. Key eligibility criteria were indication for radiotherapy after previous radical prostatectomy for prostate cancer, prostate-specific antigen less than 5 ng/mL, absence of metastatic disease, and written consent. Participants were randomly assigned (1:1) to add 6 months of ADT (short-course ADT) or 24 months of ADT (long-course ADT) to radiotherapy, using subcutaneous gonadotrophin-releasing hormone analogue (monthly in the short-course ADT group and 3-monthly in the long-course ADT group), daily oral bicalutamide monotherapy 150 mg, or monthly subcutaneous degarelix. Randomisation was done centrally through minimisation with a random element, stratified by Gleason score, positive margins, radiotherapy timing, planned radiotherapy schedule, and planned type of ADT, in a computerised system. The allocated treatment was not masked. The primary outcome measure was metastasis-free survival, defined as metastasis arising from prostate cancer or death from any cause. The comparison had more than 80% power with two-sided α of 5% to detect an absolute increase in 10-year metastasis-free survival from 75% to 81% (hazard ratio [HR] 0·72). Standard time-to-event analyses were used. Analyses followed intention-to-treat principle. The trial is registered with the ISRCTN registry, ISRCTN40814031, and ClinicalTrials.gov , NCT00541047 . Findings Between Jan 30, 2008, and July 7, 2015, 1523 patients (median age 65 years, IQR 60–69) were randomly assigned to receive short-course ADT (n=761) or long-course ADT (n=762) in addition to postoperative radiotherapy at 138 centres in Canada, Denmark, Ireland, and the UK. With a median follow-up of 8·9 years (7·0–10·0), 313 metastasis-free survival events were reported overall (174 in the short-course ADT group and 139 in the long-course ADT group; HR 0·773 [95% CI 0·612–0·975]; p=0·029). 10-year metastasis-free survival was 71·9% (95% CI 67·6–75·7) in the short-course ADT group and 78·1% (74·2–81·5) in the long-course ADT group. Toxicity of grade 3 or higher was reported for 105 (14%) of 753 participants in the short-course ADT group and 142 (19%) of 757 participants in the long-course ADT group (p=0·025), with no treatment-related deaths. Interpretation Compared with adding 6 months of ADT, adding 24 months of ADT improved metastasis-free survival in people receiving postoperative radiotherapy. For individuals who can accept the additional duration of adverse effects, long-course ADT should be offered with postoperative radiotherapy. Funding Cancer Research UK, UK Research and Innovation (formerly Medical Research Council), and Canadian Cancer Society

Calibration of Photoacoustic Spectrometers at Reduced Pressure Using Aerosols or Ozone-Laden Gas

&amp;lt;p&amp;gt;The scattering and absorption of light by atmospheric aerosols are constrained poorly in climate models. In particular, there is large uncertainty in aerosol light absorption arising from a lack of accurate measurements for absorbing aerosols. Photoacoustic spectroscopy (PAS) is the technique of choice for contact-free light absorption measurements by aerosol particles. In PAS instruments, the light intensity of a laser source is modulated periodically at typical frequencies in the range 1 &amp;amp;#8211; 2 kHz and the light absorbing species of interest absorbs energy from this modulated light. The absorbed energy is subsequently transferred to translational degrees-of-freedom of the surrounding bath gas through collisional relaxation and generates an acoustic pressure wave that is detected by a sensitive microphone. The recorded amplitude of the microphone response is related directly to the sample absorption coefficient, while the phase shift of the microphone response with respect to the laser power modulation provides information on the timescale for energy transfer to the bath gas.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;Recent years have seen PAS instruments deployed in the field on aircraft measurement platforms. These airborne studies facilitate spatially-resolved measurements of aerosol light absorption, including with variation in altitude. The accuracy of the resulting aerosol absorption measurements depends chiefly on the calibration of the PAS microphone response. Moreover, this calibration for microphone response varies with pressure, with an increased sample pressure dampening the microphone membrane motion to a greater extent. This pressure-dependent microphone sensitivity is particularly pertinent to measurements from aircraft platforms that sample at varying pressures typically over the range 400 &amp;amp;#8211; 1000 mbar. Largely, field instruments have used ozone-laden gas to calibrate PAS instruments operating at visible wavelengths, and repeated this calibration for several values of absolute pressure.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;In this contribution, we report photoacoustic amplitude and phase shift measurements which demonstrate ozone-laden gas is a poor calibrant of PAS instruments operating at visible wavelengths and at pressures reduced from those at ambient conditions (~1000 mbar). The nascent photodissociation products following photoexcitation of O&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt; do not liberate their energy to the surrounding bath gas on a fast timescale compared to the photoacoustic modulation frequency regardless of the bath gas composition. Instead, we show that the PAS instrument can be calibrated at ambient pressure and then a miniature speaker can be used to excite an acoustic response for calibrating the pressure sensitivity in the microphone response. In this way, we show that we accurately measure aerosol absorption at reduced pressure for sub-micrometre diameter aerosols consisting of dyed polystyrene latex spheres or nigrosin dye. These results will be of utmost interest to those measuring aerosol absorption using PAS from airborne platforms or those calibrating PAS instruments for ground based or laboratory measurements.&amp;lt;/p&amp;gt; </jats:p