Comparison of the U&amp;lt;sub&amp;gt;37&amp;lt;/sub&amp;gt;&amp;lt;sup&amp;gt;K′&amp;lt;/sup&amp;gt;, LDI, TEX&amp;lt;sub&amp;gt;86&amp;lt;/sub&amp;gt;&amp;lt;sup&amp;gt;H&amp;lt;/sup&amp;gt; and RI-OH temperature proxies in the northern shelf of the South China Sea