Reply to comment by Ben-Zvi,A., D. Rosenfeld and A. Givati on the paper: Levin,Z., N. Halfon and P. Alpert, “Reassessment of rain experiments and operations in Israel including synoptic considerations,” Atmos. Res. 97, 513–525. DOI: 10.1016/j.atmosres.2010.06.011

Levin et al. (2010; hereafter LHA) (Levin, Z., Halfon, N., Alpert, P., 2010. Reassessment of rain experiments and operations in Israel including synoptic considerations. Atmos. Res. 97, 513–525. DOI:10.1016/j.atmosres.2010.06.011.), reanalyzed the results of the operational seeding in northern Israel between 1975 and 2007 and the preceding Israel 2 cloud seeding experiment (1969–1975) and concluded that there is no net increase in precipitation over the target areas. Our analysis revealed that a synoptic bias during Israel 2 is one of the reasons for the apparent positive effect of seeding in the northern target area and the negative effect in the southern area both of which disappeared in the following experiment in the south (Israel 3; 1975–1995) and the operational seeding in the north.Ben-Zvi et al. (2010;hereafter BRG) criticized our paper primarily on the ground that we did not consider the positive results of Israel 1 experiment (1960–1967). It should be noted that in Israel 1 different seeding lines were used from those in both Israel 2 and the operational period. In addition, its raw data is not accessible anymore for reanalysis. Furthermore, Israel 2 had been designed as a confirmatory cross-over experiment to Israel 1 and failed to reproduce its promising results with double ratio (DR) of ~ 1.00, namely, zero rainfall enhancements. The same DR values were also found in Israel 3 and in the operational seeding. Therefore, because of the differences in the two experiments, the lack of access to the raw data and the disappointing results of the confirmatory experiment, we decided to concentrate our analysis on the more recent seeding activities.The attempt by BRG to explain the reduction of the DR to ~ 1.00 in the operational seeding period by the suppression due to pollution have been disproved by Alpert et al., 2008, Alpert et al., 2009 and also fail to explain the sharp decline of the target/control ratio right at the beginning of the operational seeding period when the lucky draw in this area came to its end (see LHA).     

Comment on “Trends and low frequency variability of extra-tropical cyclone activity in the ensemble of twentieth century reanalysis” by Xiaolan L. Wang,Y. Feng,G. P. Compo,V. R. Swail,F. W. Zwiers,R. J. Allan,and P. D. Sardeshmukh,Climate Dynamics, 2012

The main subject of this article is to comment on the issue of storminess trends derived from the twentieth century reanalysis (20CR) and from observations in the North Atlantic region written about in Wang et al. (Clim Dyn 40(11–12):2775–2800, 2012). The statement that the 20CR estimates would be consistent with storminess derived from pressure-based proxies does not hold for the time prior to 1950.     

Global warming vs. climate change, taxes vs. prices: Does word choice matter?

Does ??climate change?? seem like a less serious problem than ??global warming?? to Americans and Europeans? Does describing the costs of climate change mitigation in terms of ??higher taxes?? instead of ??higher prices?? reduce public support for such efforts? In an experiment embedded in an American national survey, respondents were randomly assigned to rate the seriousness of ??global warming,?? ??climate change,?? or ??global climate change.?? Contrary to predictions made by a leading political strategist, the full sample and political Independents perceived ??climate change?? and ??global warming?? to be equally serious. Among Republicans, ??climate change?? was perceived to be more serious than ??global warming,?? whereas the reverse was true among Democrats. A similar experiment embedded in a survey of residents of 31 European countries showed that ??global warming?? and ??climate change?? were perceived to be equally serious problems. And an experiment embedded in an American survey showed that describing the increased costs of climate change mitigation legislation via ??higher taxes?? instead of via ??higher prices?? did not reduce popular support for such legislation, also contradicting a political strategy memo. Thus, word choice may sometimes affect public perceptions of the climate change seriousness or support for mitigation policies, but a single choice of terminology may not influence all people the same way, making strategic language choices difficult to implement.     

Archiv Fr Meteorologie,Geophysik und Bioklimatologie,Serie A, Band Ⅳ. 1951.

在对流层的上部急流的动力稳定度和风速的的垂直分布(Uber die Vertikalver-teilung Von Widgeschwindigkeit und Schwerestabilitat in Freistrahlbewegungen deroberen Troposhare.Von C.G.Rossby,P.3—23)。从北美高空观测记录知道在200—300毫巴高度上风的分布,常常有一很长的运行甚慢的而且近乎平行的     

Archiv Fr Moteorologie, Geophysik und Bioklimatologie,Serie B, Band Ⅲ. 1951.

信风环流及赤道西风带(Passatzirkulation und Aquatorial Westwindzone.VonH.Flohn,P,1—15)。在近赤道处,除了地面和高空的主要风系以外,作者证明在热带东风带内,还有一经向信风环流。在近地面气流有一向热赤道的分速,     

What (science for) adaptation to climate change in Colombian agriculture? A commentary on “A way forward on adaptation to climate change in Colombian agriculture: perspectives towards 2050” by J. Ramirez-Villegas, M. Salazar, A. Jarvis, C. E. Navarro-Valcines

Climate change is putting Colombian agriculture under significant stress and, if no adaptation is made, the latter will be severely impacted during the next decades. Ramirez-Villegas et al. (2012) set out a government-led, top-down, techno-scientific proposal for a way forward by which Colombian agriculture could adapt to climate change. However, this proposal largely overlooks the root causes of vulnerability of Colombian agriculture, and of smallholders in particular. I discuss some of the hidden assumptions underpinning this proposal and of the arguments employed by Ramirez-Villegas et al., based on existing literature on Colombian agriculture and the wider scientific debate on adaptation to climate change. While technical measures may play an important role in the adaptation of Colombian agriculture to climate change, I question whether these actions alone truly represent priority issues, especially for smallholders. I suggest that by i) looking at vulnerability before adaptation, ii) contextualising climate change as one of multiple exposures, and iii) truly putting smallholders at the centre of adaptation, i.e. to learn about and with them, different and perhaps more urgent priorities for action can be identified. Ultimately, I argue that what is at stake is not only a list of adaptation measures but, more importantly, the scientific approach from which priorities for action are identified. In this respect, I propose that transformative rather than technical fix adaptation represents a better approach for Colombian agriculture and smallholders in particular, in the face of climate change.     

The tidal jet in Rupert‐Holberg inlet,B.C.

Abstract

Observations of the tidal jet issuing from Quatsino Narrows into Rupert‐Holberg Inlet, B.C. are discussed. Two types of flow are observed: a buoyant surface jet and a negatively buoyant jet. The buoyant flow is parameterized with an initial densimetric Froude number, and agreement is good between the observed vertical penetration of the jet and that predicted by several existing models. The negatively buoyant jet entrains several times its initial volume; entrainment constants for the flow are larger than those observed from the two‐dimensional plume on similar inclines, yet smaller than those for neutrally buoyant jets. A time‐scale of 2 to 3 weeks is calculated for the flushing of the Inlet during times of negatively buoyant inflow. The buoyant jet is observed to reduce the overall density of the water column, and estimated vertical eddy diffusivities are considerably larger than in most other fjords. Changes in the Froude number of the jet are controlled primarily by changes in the density and speed of the inflow. During the period of observations the density of the jet appears to be controlled by runoff.