pan><span class="o">.</span><span class="n">ma</span><span class="o">.</span><span class="n">array</span><span class="p">(</span><span class="n">obs</span><span class="p">[</span><span class="n">i</span><span class="p">,</span> <span class="p">:,</span> <span class="p">:]</span> <span class="o">-</span> <span class="n">clim</span><span class="p">)</span>
        <span class="n">numerator</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">sum</span><span class="p