scholarly journals The Role of Land–Sea Topography in Blocking Formation in a Block–Eddy Interaction Model

2006 ◽  
Vol 63 (11) ◽  
pp. 3056-3065 ◽  
Author(s):  
Dehai Luo ◽  
Zhe Chen
Keyword(s):  
Large Scale ◽  
Theoretical Study ◽  
Interaction Model ◽  
Synoptic Scale ◽  
Westerly Jet ◽  
Blocking High ◽  
Dipole Component ◽  
Large Scale Land ◽  
Northern And Southern Hemispheres

Abstract This paper is an extension of a theoretical study by Luo on the effect of large-scale land–sea contrast (LSC) topography on the formation of an eddy-driven blocking. It is found that the topography term can be included explicitly in the blocking evolution equation because of the inclusion of the higher-order wave–topography interaction. Although the blocking flow cannot be excited purely by the LSC topography, the LSC topography is found to be capable of enhancing the amplification of the dipole component in a blocking flow associated with upstream synoptic-scale eddies. In this case, a strong omega-type blocking high can be driven by the joint action of synoptic-scale eddies and LSC topography. This seems to provide an explanation of a difference in blocking intensity between the Northern and Southern Hemispheres. The most important finding of this paper is that in the presence of LSC topography the double jets that appear during the onset of an eddy-driven dipole block collapse into a strong single westerly jet that is within the south side of an omega-type blocking high, which is different from the result predicted by the theoretical model proposed in Luo’s previous work.

FAMILY FARMS IN AUSTRIA, ITALY AND POLAND

AGROFOR ◽  
2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Erika QUENDLER ◽  
Adriano CIANI ◽  
Malgorzata PINK
Keyword(s):  
Large Scale ◽  
Census Data ◽  
Labour Force ◽  
Family Farms ◽  
Legal Form ◽  
The Family ◽  
Agricultural Census ◽  
The Status ◽  
Large Scale Land

Recently there has been a surge of interest in family farms – in particular because2014 was declared by the United Nations as the International Year of FamilyFarming. This focus on family farms is mainly a reaction to several trends, such aseconomic pressures, large-scale land grabbing or the restructuring of agrifoodchains, etc. Yet it has to be acknowledged that the changes taking place inagriculture and agrifood systems put into question the role of family farms. Thispaper responds to the need for a review of family farms by examining the situationin Austria, Italy and Poland. It uses the legal form ‘sole holder’ as the criteria toidentify the family farm. It analyses the status of family farms in terms of (I)numbers, area cultivated, livestock and labour force, (II) their contribution tonutrition and food security, and (III) their consideration within the relevantagricultural policies. The situations in Austria, Italy and Poland are outlined usingofficial agricultural census data, 2013. The results show that family farms are byfar the prevailing form of agriculture in these three countries. Furthermore, weexplore the country specific characteristics within the policy environment given inwhich family farms operate and how this policy supports them. Finally, this formof farm poses significant challenges for food production and systematic policydesign. We conclude by giving some suggestions on future perspectives and theareas for further research.

The Law and Land Grabbing: Friend or Foe?

2014 ◽  
Vol 7 (2) ◽  
Author(s):  
Liz Alden Wily
Keyword(s):  
Large Scale ◽  
Land Rights ◽  
Customary Law ◽  
Sub Saharan Africa ◽  
Land Acquisitions ◽  
Customary Rights ◽  
Sub Saharan ◽  
Large Scale Land ◽  
Customary Land

AbstractThis paper reflects upon the role of law in the contemporary surge in global large-scale land acquisitions. Its point of reference is the land security of several billion rural poor who traditionally own and use untitled lands that are classified as state lands or unowned public lands in national laws. Most of the affected lands are off-farm areas including forests, marshlands, and rangelands. Investors target these lands in belief they are unowned. Governments concur, selling or leasing these lands on grounds of being technically the lawful owner and despite awareness that these lands are occupied and used. Despite the longstanding nature of such conflicts as well known and long debated, the present land rush brings unresolved contradictions between statutory and customary law and associated meanings of property firmly to the fore. Using Sub-Saharan Africa as the example, this paper examines the legal effects. It is shown that while millions of local land rights are threatened, the land rush also vitalises demands for improved national law status for unregistered customary rights, including those such as forest and rangelands purposely held by communities in common. To this extent, the contemporary rush could prove as much legal friend as foe to majority land rights in agrarian economies. This is partly because the current rush, unlike those that have gone before it, occurs in an environment of advanced popular communication, emergent mass empowerment, and has the advantage of a pre-rush era of legal improvement in the handling of indigenous and customary land rights that has established alternative precedents. Opportunities to coerce modification of classical dispossessory paths of economic growth strongly exist. Global advocacy for secure community land rights is rapidly advancing.

scholarly journals A Barotropic Envelope Rossby Soliton Model for Block–Eddy Interaction. Part I: Effect of Topography

2005 ◽  
Vol 62 (1) ◽  
pp. 5-21 ◽  
Author(s):  
Dehai Luo
Keyword(s):  
Large Scale ◽  
Plane Channel ◽  
Geographical Location ◽  
Synoptic Scale ◽  
Analytical Treatment ◽  
Soliton Model ◽  
Zonal Scale ◽  
Planetary Scale ◽  
Dipole Component ◽  
Zonal Wavenumber

Abstract A new forced envelope Rossby soliton model in an equivalent barotropic beta-plane channel is proposed to describe the interaction between an incipient block (planetary scale) and short synoptic-scale eddies. This model is based on two assumptions, motivated by observations that (i) there exists a zonal scale separation between the planetary-scale and synoptic-scale waves and (ii) that the range of synoptic-scale zonal wavenumber is comparable to the planetary-scale zonal wavenumber. These assumptions allow an analytical treatment. The evolution of the planetary-scale block under the influence of synoptic-scale eddies is described by a forced nonlinear Schrödinger equation that is solved numerically, while the feedback of block development on the preexisting synoptic-scale eddies is derived analytically. It is shown that the planetary-scale projection of the nonlinear interaction between synoptic-scale eddies is the most important contributor to the amplification and decay of the planetary-scale blocking dipole or anticyclone, while the synoptic–planetary-scale interaction contributes significantly to the downstream development of preexisting synoptic-scale eddies. Large-scale topography plays a secondary role compared to the synoptic-scale eddies in exciting the block. However, it plays a role in inducing a standing planetary-scale ridge prior to block onset, which fixes the geographical location of the block and induces meridional asymmetry in the flow. In particular, the topographically induced planetary-scale ridge that is almost in phase with a dipole component of blocking flow is found to be a controlling factor for the northward deflection of storm tracks associated with blocking anticyclones.

scholarly journals The amplification of Madden-Julian Oscillation boosted by temperature feedback

2021 ◽  
Author(s):  
Guosen Chen
Keyword(s):  
Latent Heat ◽  
Large Scale ◽  
Theoretical Study ◽  
Interaction Model ◽  
Energy Generation ◽  
Warm Pool ◽  
Madden Julian Oscillation ◽  
Rotation Effect ◽  
Temperature Feedback ◽  
Temperature Tendency

AbstractDue to small Coriolis force in tropics, the theoretical study of Madden-Julian Oscillation (MJO) often assumes weak temperature gradient balance, which neglects the temperature feedback (manifested in temperature tendency term). In this study, the effect of the temperature feedback on the MJO is investigated by using the MJO trio-interaction model, which can capture the essential large-scale features of the MJO.The scale analysis indicates that the rotation effect is strong for the MJO scales, so that the temperature feedback is as import as the moisture feedback (manifested in moisture tendency term), the latter is often considered to be critical for MJO. The experiments with the theoretical model show that the temperature feedback has significant impact on the MJO’s maintenance. When the temperature feedback is turned off, the simulated MJO cannot be maintained over the warm pool. This is because the temperature feedback could boost the energy generation. Without temperature feedback, only the latent heat can be generated. With temperature feedback, not only the latent heat but also the enthalpy (and therefore the available potential energy) can be generated. Therefore, the total energy generation is more efficient with temperature feedback, favoring the self-maintenance of the MJO. Further investigation shows that this effect of the temperature feedback on MJO amplification can be inferred from observations.The findings here indicates that the temperature feedback could have non-negligible impacts on MJO, and have implications in the simulation of MJO.

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