首先,让我们解释什么是压缩。(压缩)[1]的定义是衡量一个包裹的相对体积变化的流体对压力变化的反应。当我使用Matlab计算海水的压缩性和[海水包][2](相当于(Fofonoff &米勒德,1983)[3]),我获得的压缩性增加在寒冷的温度下咸、咸水和淡水。事实上,水最小压缩系数在46.5°C([好& Millero, 1973] [4])。随着压力的增加矿化度的压缩减少任何考虑。![压缩压力和温度的范围][5]在图中可以看出任何盐度的压缩性是最大的在低温下(不仅仅是海水)和压力。一般而言,水的压缩性是最大的在低温下由于水的内部结构。逆与温度的关系似乎也接受了([& Millero, 1973][6])和与其他属性有直接关系的声音的速度。压缩在一个典型的液体,在低温下降低结构更加紧凑。在水里,有一个变化在低温下向更开放的结构(集群)[7](扩大二十面体水集群)和密集的集群(倒塌的二十面体水集群)。 As the water structure at lower temperatures is more open, the capacity for it to be compressed increases. As cold liquid water is heated it shrinks, it becomes less easy to compress, the speed of sound within it increases, gases become less soluble and it is easier to heat. The compressibility above is calculated using the formula in the figure (same as in the [wiki article][8]) and I have included the code to reproduce the results: T=-2:1:30; P=0:10:1000; S=35; for i=1:length(T) for j=1:length(P) dens(i,j)=sw_dens(S,T(i),P(j)); dens15(i,j)=sw_dens(15,T(i),P(j)); dens0(i,j)=sw_dens(0,T(i),P(j)); end end spvo=1./dens; spvo15=1./dens15; spvo0=1./dens0; for i=1:length(T) for j=1:length(P)-1 % Ev2(i,j)=-(1./spvo(i,j))*(spvo(i,j+1)-spvo(i,j))./(P(j+1)-P(j)); Ev35(i,j)=(1-spvo(i,j+1)/spvo(i,j))/(P(j+1)-P(j)); Ev15(i,j)=(1-spvo15(i,j+1)/spvo15(i,j))/(P(j+1)-P(j)); Ev0(i,j)=(1-spvo0(i,j+1)/spvo0(i,j))/(P(j+1)-P(j)); end end figure(1);clf for j=[1,20,100] line(T,Ev35(:,j),'Color','k','LineWidth',2); line(T,Ev15(:,j),'Color','b','LineWidth',2); line(T,Ev0(:,j),'Color','r','LineWidth',2);axtt end text(T(20),Ev35(20,1),['P=',num2str(P(2)),'dbar']) text(T(20),Ev35(20,20)*.99,['P=',num2str(P(21)),'dbar']) text(T(20),Ev35(20,100)*.98,['P=',num2str(P(101)),'dbar']) text(T(15),Ev0(15,1),['P=',num2str(P(2)),'dbar'],'Color','r') text(T(15),Ev0(15,20)*.99,['P=',num2str(P(21)),'dbar'],'Color','r') text(T(15),Ev0(15,100)*.99,['P=',num2str(P(101)),'dbar'],'Color','r') xlabel('Temperature (degC) ') ylabel('Compressibility (1/dbar) ') legend('35 PSU','15 PSU','0 PSU') text(7,5e-6,'$c_w=-{1\over V}({dV\over dp})$','Interpreter','latex','FontSize',20,'FontWeight','bold') [1]: http://en.wikipedia.org/wiki/Compressibility [2]: http://www.marine.csiro.au/datacentre/processing.htm [3]: http://agris.fao.org/agris-search/search.do?recordID=AV20120150138 [4]: http://dx.doi.org/10.1063%2F1.1679903 [5]: http://i.stack.imgur.com/DsUB4.png [6]: http://dx.doi.org/10.1063%2F1.1679903 [7]: http://www1.lsbu.ac.uk/water/clusters.html [8]: http://en.wikipedia.org/wiki/Compressibility